How can you reset the shift to park in a 07 Cadillac sts4 push start by using the driver side door.

Could be the interlock brake switch . don't guess an just replace parts . You don't know how to test , take it to someone who can .

Something wrong with the shift lock system maybe. Safety system that won't allow the gear selector to move from park unless the driver is pushing the brake pedal . Do your brake light's work ? Does your caddy have floor or column shift ?
Automatic Transmission Shift Lock Control Description and Operation (Floor Shift)
The automatic transmission shift lock control system is a safety device that prevents an inadvertent shift out of PARK when the engine is running. The driver must press the brake pedal before moving the shift lever out of the PARK position. The system consists of the following components:
• The automatic transmission shift lock solenoid (serviced as the automatic transmission shift lock actuator), as well as the body control module (BCM) and the engine control module (ECM).The shift lock solenoid is located within the floor shift control assembly with vehicles equipped with floor shift.
• The BCM controls the voltage supply circuit of the shift lock control solenoid. The following conditions must be before the BCM will supply voltage to the shift lock control solenoid.
The BCM controls the voltage to the shift lock control solenoid through the shift lock control solenoid controlled voltage circuit. The following conditions must be met before the BCM will supply voltage to the shift lock solenoid:
• The ignition is in the ON position.
• The ECM sends an input via GMLAN serial data to the BCM indicating the transmission is in the PARK position.
• The BCM determines the brake pedal is applied according the brake pedal position.
Since the shift lock control solenoid is permanently grounded, the BCM supplies voltage to the automatic transmission shift lock control solenoid, mechanically unlocking the shift lever allowing the driver to move the shift lever out of the PARK position as the solenoid energizes. When the brake pedal is not applied, the BCM turns the control voltage output of the shift lock control solenoid OFF, de-energizing the shift lock control solenoid. The de-energized solenoid mechanically locks the shift lever in the PARK position.
During remote start operation, the BCM will de-energize the shift lock control circuit, locking the shift lever in the PARK position.

door lock actuator came off outside door handle. Remove it and have a new clip on hand for the rod.

Your key is stuck ? It won't move , it won't come out of the lock cylinder ? Can you shift it from park to drive , neutral etc... Are there any lights lit on the dash , yellow wrench light , service vehicle soon light ? any messages on Driver Information Center ? Your Cadillac has numerous electronic features controlled by modules - computers ! If your not familiar with electronics an these things I suggest you take it to someone who is . Does you Cadillac have console fool shifter ?
Electronic Park Lock (EPL)/Ignition Lock Cylinder Control Actuator: If the vehicle is equipped with automatic transmission and a floor mounted console gear shift, it has an ignition lock cylinder control actuator system in the steering column. The ignition lock cylinder control actuator purpose is to prevent the ignition key from being turned to the OFF position when the transmission is in any position other than PARK and the vehicle may still be moving. The column ignition lock system consists of an ignition lock cylinder control actuator, and a park position switch that is located in the automatic transmission shift lock control switch. The ignition lock cylinder control actuator contains a pin that is spring loaded to mechanically prevent the ignition key cylinder from being turned to the lock position when the vehicle transmission is not in the PARK position. If vehicle power is lost, and/or the transmission is not in the PARK position the operator will not be able to turn the ignition key to the lock position and will not be able to remove the ignition key from the column.
Linear Shift Assembly: If the vehicle is equipped with a column mounted gear shift, it has a linear shift assembly on the steering column. The linear shift assembly has a cable that runs from the linear shift assembly to the ignition lock cylinder case. The purpose of this cable is to prevent the ignition key from being turned to the OFF position when the transmission is in gear and the vehicle may still be moving. The linear shift assembly cable contains a pin that is spring loaded to mechanically prevent the ignition key cylinder from being turned to the lock position when the vehicle transmission is not in the PARK position. If vehicle power is lost, and/or the transmission is not in the PARK position the operator will not be able to turn the ignition key to the lock position and will not be able to remove the ignition key from the column.
The windows are no exception , they are controlled by modules in each door an are connected by a serial data communication bus !
The vehicle is equipped with power windows controlled by the door modules. Each passenger door window can be operated, either from a power window switch built into the driver door switch assembly (DDSA) , or, from a power window switch mounted locally on its associated door. The driver door window can be operated only from the driver door power window switch built into the DDSA.
When the driver door module (DDM) receives a driver door window switch request from the DDSA, the DDM examines the request and inspects to see if it has received any messages from any of the other vehicle modules prohibiting the movement. If no prohibitive messages have been received, the DDM then applies power and ground to the driver door window motor to move the window as requested.
When a passenger door module, passenger front door module (PDM), LH rear door module (LRDM), or RH rear door module (RRDM), receives a window switch request from, either the DDSA or the window switch mounted locally to its door, the passenger door module examines the request and inspects to see if it has received any messages from any of the other vehicle modules prohibiting the movement. If no prohibitive messages have been received, the passenger door module then applies power and ground to its associated window motor to move the window as requested.

Just turn the car on, but Dont start it and put it in nutruel then start it... This she work til you can afford to fix it...

Lets start by checking your brake light switch.
Your car has a switch on the brake pedal that not only makes the brake lights come on, but also tells the transmission it can shift out of park.
This really may be 2 separate switches, but should be under the dashboard and both should "open" when you push the brake pedal down.
Take a good flashlight and look.
The switches are small, about the size of your thumb, and both should have 2 wires attached to them.
Be blessed.

The most commonly diagnosed component is the shifter and/or shifter solenoid on your Impala.
GM issued a bulletin on this problem. Contact your dealer, they are aware of the problem and you could be covered under warranty. Below is a copy of the bulletin.

#08-07-30-007A: EI08045 - Key Cannot be Removed from Ignition with Gear Selector in Park, Shifter Cannot be Moved From Park Position (Engineering Information) - (Apr 8, 2008)

Subject: EI08045 -- Key Cannot Be Removed from Ignition with Gear Selector in Park, Shifter Cannot Be Moved From Park Position (Engineering Information)

Models: 2007-2008 Chevrolet Impala
Good luck, i hope this helps.

does the gear shifter move? if the gear shifter moves and it wont shift then you have broken linkage, if it wont move you may have ignition linkage problems or the button may not be pushing in all the way, also the brake pedal is tied in too

The pressure control solenoid needs to be replaced. It"s under the side cover on the transmission on drivers side. Not a simple fix at home. You will also need a side cover gasket. The transmission does not need to be rebuilt.

they shift interlock is not releasing...possible cause a blown fuse or bad brake light switch.if you need to get it out of park to get to a dealer ther is a manual release..look for a small opening around the shifter...once you start the vehicle push a phillip screw driver through the opening and push the release...pull into gear.....do not use this release constantly it can cause computer problems