How can I reset the light by myself?

Check engine or the oil change light?
Check engine you have to have a scanner.
Oil change light check owners manual for procedure.

Thanks. Its my engine light. I was afraid that was the only way to shut off the light. The scanner tells me i have something wrong with my catalyic converter but i had the emmissions tested and it would still pass.

You are welcome.
Many things can cause a cat code.
O2 sensors ,engine missfire or rich exhaust and other sensors.
Check basic engine tune up first.
Good luck
MT