How to change an Item into a different one?

So, Im working on a Forge mod on Java 1.17.1, and I wanted to try a procedure, that when you put an item in a cauldron, lets say youll leave it there for five in game days, It would turn into a Different Item, I couldnt find any question like this, so Im making my own, and I dont know if it is possible. Or if theres an other way to make this other than using a cauldron, I would still like to hear and know other tips to use.

Thank you.