How do we get the check engine oil light off of a 1999 chevy 6 liter

This works for most Chevy trucks:
Turn key to ON position;
Press accelerator 3 times within 5 seconds;
If Change Oil Service light blinks twice,you have sucessfully reset the change oil light.

First turn the key to the run position, (not start). Push the gas pedal down to the floor 3 times within five seconds. Turn the key off and then cycle back on and start the truck. The indicator should flash five times and go out.
It may take a few tries.