Invoices are sent on a 4-week billing cycle, so if you had received an invoice on January 1st, for example, your next invoice will be sent 4 weeks later on January 29th.
In your portal account, you can reschedule and cancel sessions on your own. Simply click on the session in your calendar and choose either Reschedule or Cancel. How to Reschedule Your Session: Open your portal calendar and click on the session that ...