Exchange unopened iPhone 17pro DB for silver?

My wife’s iPhone 17pro is coming Tuesday. However she ordered the wrong color and couldn’t change it. She wanted silver.

Hypothetically let’s say I had the 17pro deep blue unopened box now, an AT&T has silver in stock would I be able to exchange it?

Now a co worker of mine mentioned to do it another way but I don’t know how it will go. He said order a new line for pick up, pay the taxes etc and when you pick it up say you changed your mind you want to exchange deep blue for the silver on the line.

Any recommendations? Thanks!