I add to, delete from, and cancel my autoships all the time. They do inform you at least 48 hours ahead of time so you can make changes to it, choose the day you want it, push it out, etc. Very easy to do. I don't know that you can say "I want it on Monday".I have substituted Tiny Tiger successfully as well. A question of my own about autoship....I called and asked but the woman I spoke to was not that informative which was odd as they usually do bend over backwards to help you. Is it difficult to add or delete and do you get the shipment on the same day each week? The rep never even mentioned an email coming before they ship.