The best sell it by your self, trade in always get low price as the reseller need to make profit later on

Question about trade in at apple store. I need time to ensure all my important stuff are transferred to new phone. If i order through apple website, will they give an option to drop in the used phone at the trx apple store within 14 days of receiving the new phone?

How about if i pay online but physical pick up the new phone at the store, do they allow me to come back within 14 days to drop the used phone?