How do I make a changing world?

How do I make it so that the world changes aroud the player, as in once the player leaves an area then goes back it has rearranged.

You mean like a platformer where when you go back you see another environment?

So because I don't know what you want here are just a few thoughts.

If it should happen at a certain stage then I would try it with an invisible hitbox.

So when objPlayer goes back you just check with another condition if the hitbox is now gone or set a variable.

If you want it all the time - then I would try to create or set the new environment visible as soon as it is e.g. 100px outside of my window . And at the same time destroy the old one (or set invisible).

fm4fanAT i want exactly what you mentioned I just want to know what series of events I need to make it work.