Once you reach the part with the mistake, the engineer will record you as you sing it the correct way. Shortly after you pass this point you will stop and once again listen to the recording. It is also used to fix incorrect notes from instruments. This process does not work well with drum mistakes. If you are a band, you will find out that many engineers will spend the majority of time working with the drum sound.
Drums are the most difficult to record, and require the most time.
This is because a singer, bass guitar, keyboard, etc, requires only one microphone. A set of drums may use 10 or more microphones. Each must be separately mixed and blended to create a good sound. Effects are added during mixdown. When you actually are recording, the effects are left out of the headphones you wear so that you are not distracted.