Upgrading iPhone 16 Pro Max to 17 Pro Max at Qatar Airport Store

I will be on a transit stop at Qatar airport and I would like to upgrade the 16 pro max to 17 pro max 512 giga

how much it will cost me and can i do it on spot or I need to make a reservation fist

[Re-Titled by Moderator]

Original Title: i need to replace my 16 pro max with an 17 pro max from the store at Qatar air port