You need to be more descriptive in your request.
What kind of cheat exactly?
If you want to change their health, then YES, you could use the action
plraddhealth=x in your script.
If you want to revert a level, then NO, the levels can only advance in a forward sequence.
It all depends on what you want your "cheat" to be as to whether or not it can be scripted.
Also, what action would you like to perform the cheat?
Pressing a key, finding a hidden room, or placing a certain object at a particular location.
Again, you need to be more descriptive in your request.