The outer door frame CAN be replaced if you like. You can view an exploded view diagram at searspartsdirect.com. Just type in your model number and locate item 10 under the "Door" parts listing. The part comes in various colors so make sure you select the correct one.
The door can be easily removed by opening it all the way and lifting straight up at the hinges. The door will come off the hinge pins and can be laid on a flat surface for easier access. Place a layer of towels under the door to prevent damage to the door.
You will need to remove the door handle to get the outer door frame off. To access the door handle mounting screws on MOST microwave ovens
, you have to remove the inner door panel that goes around the perimeter of the glass. You can use a small screwdriver to carefully pry the plastic up and work
your way slowly around the perimiter of the glass. Most microwave ovens
also have grooves in the panel that you can insert the screwdriver into. Use care not to pry against the glass. The glass is tempered and also has an RF shield that prevents harmful microwaves
from potentially harming the consumer. If you break the glass, you may need to purchase a new door.
The door handle screws are located behind the inner panel. Remove the door handle and and locate any screws that may be securing the outer door (front) frame in place. Once you install the new outer door frame, re-install the door handle and carefully re-insert the inner door panel. Gradually work
your way around the perimeter of the door glass and make sure it snaps back into place.
If you have questions about this repair, please let me know. I hope this helps you.
To answer your initial question, the microwave should continue to be safe to use as long as the inner door seal and door glass are intact. Make absolutely sure you reinstall the door components back together properly. Not doing so will render the oven unsafe to use. Refer to the web site I provided as a reference for how the door components go back together.
NOTE: This part is listed a bit cheaper at appliancepartspros.com. Use the part number from the first website I mentioned as your search criteria.