Hello, @FaithHopeLove I will share this thread with you as it should help answer your questions.
@Silversitters has also provided some really helpful answers and things to consider about this 
@FaithHopeLove If the sitter has a confirmed sit booked where the dates go past their membership period then they should be on auto-renewal so that their membership won’t expire mid-sit. If the member tries to cancel their auto-renewal then they will get a pop-up saying they can’t as they have an active sit and would need to cancel the sit first.
There is a more in-depth explanation on the above thread so will be worth a read and hopefully help more
If you have any questions about the process or to ask about your specific sit you can reach out to the Membership Services team at support@trustedhousesitters.com they will be happy to help.