Is it possible for some snakes to change their gender?

AnswerTake it to the vet and have them probe it to check for sex.

You can look at the belly scales of the snake. If it has wavy scales it is a female if not wavy male.<---- This statement is folk lore at best. There is no scientific evidence that a snakes sex can be determined from the shape of scales. The only definitive way to sex a snake is to either probe (a very dangerous procedure which should only be conducted by thoqualified) or to take an x-ray. As it's cheaper to probe, that is my recommendation for all owners, even if you have to take it to your vet for the first few times and taught how.