What happens to my calls if I cancel the AI Receptionist?

Your own number never changes. If you cancel the AI Receptionist in Add-ons, it keeps working until the end of the period you've paid for and isn't charged again.

After it ends, AOS stops answering and texting. Your phone company keeps forwarding missed calls to the AOS number until you tell it not to, and those calls then only reach the phone you set to ring first (if you set one); otherwise callers hear that the number isn't taking calls. So switch forwarding off before the end date: open Phone, then Keep your number, and use “How to turn it off”. For example, dial *73 on Verizon or Visible, or ##004# on T-Mobile, AT&T and most other mobile carriers.