The cobalt says change oil soon, but the oil just got changed. How do I program it to stop saying change oil soon?

if your Chevrolet is a 2007 right by your wheel you will fine two buttons on your right side there is one that has a line and another one that has a arrow once you hold that down for about 20sec on your instrument panel it should say oil restart once you see that press down on the arrow looking button and for about 30 sec. it should say acknowledged restored oil to a 100 %

turn your ignition to the run position and pump the gas pedal 3 times wait for dash lights to reset

If all that fails get out your owner's manual and read the instructions on how to reset after an oil change.