How can I exchange the band size in the offline store?

I ordered Apple watch SE with solo loop and one other solo loop through the online apple store. I tried measuring my wrist size using a size guide in the online store, the result came out with 7 sizes, however, all of my friends told me it would be better to purchase a smaller size for me. So, If my deliveries arrived I'm going to return immediately to the offline store. My question is if I bring new products to the offline apple store, then they are able to exchange directly for me? And also it is possible to measuring and trying the sizes at the same time in the offline store? If I do that both then when my Apple Watch arrived, do I have to make an appointment to return and offline store both? or just need to register to return nearby offline store? This is the first time to refund and exchange Apple products so I have many questions please let me know. Thank you!