One issue that prevents some Apple stores to do the swap on a online order being picked up at the store, is that their system does not immediately update the picked up order. This is why they could not do so when I picked up the order yesterday. They suggested I return today when the picked up order is on the system and they can easily do the in store return, and credit you for your configuration, and then resell you the watch with the band you desire - if more, you pay the difference, if less it is a credit to the method of payment. Luckily for me in Los Angeles, the Apple store is less than 10 minutes drive with easy parking. Neither yesterday nor today was the store particularly busy. Today I was told the next available specialist could take 30 to 40 minutes, and my named was called in less than 10 minutes. I did overhear a sales rep saying they are almost out of all watches, so maybe this is why they are not that busy. They had no iPhone 13s, no iPad minis and no watches.