Self-service internet move without an exact date?

I'm moving to a new house next month but don't know the exact date I will need service activated at the new address.  I have my own modem/router/equipment, I'm happy to set it up myself.  When I go through the process of setting up a transfer, it makes me set up a service appointment that I don't want or need.

Do I need to inform Xfinity ahead of time somehow, or can I simply move the modem to the new house and activate it?