Exchange Iphone 13 for a different colour

If you purchased the phone within the last 14 days you can simply return it and buy a new one; but you may have to wait for availability. You will not be able to simply swap it in store; but you could return it and purchase a new one again subject to availability.

Within 14 days days of purchase you can return it for a refund and then buy a different color. Good luck finding one.