Okay, so imagine you have a toy car that makes a sound when you press a button. Now, imagine you recorded that sound and saved it on your phone. Later on, you want to hear that sound louder and stronger, so you decide to play it through a big speaker.
But here's the thing: the sound that comes out of the big speaker might not be the same as the original sound you recorded. It might sound different because the speaker amplifies the sound in a different way than the toy car did.
Re-amping is what you do when you want to take that new sound from the speaker, record it again, and then change it to sound more like the original sound you recorded from the toy car. It's like taking the sound on a little journey from the toy car to the phone to the big speaker and then back to the phone to make it sound better.
Some people like to re-amp their music recordings so they can make it sound more interesting or unique or just better overall. It's like using different colored crayons to make a picture look cooler.