Answer 1

if you're talking about deallocation you can't with a function.
Once you define a function, all the space it needs is allocated and set after compilation.
If you want to reduce as much memory with thay function, review the code and make sure you're not taking up unnecessary space with variables and recursions.
If you try to delete something that didn't allocate memory during runtime you may run into undefined behavior which is worse than having a few bytes of extra memory for a function.