First of all: if you are thinking about cancelling because you have a vacation period ahead, we recommend talking to your therapist who will explain in detail the best method to freeze, without cancelling, your subscription during the time you are away: breaks! It is much more practical for these periods and you can still have access to the chat with your therapist.
But if you have decided to quit therapy or you have been discharged by your therapist, you just have to go to your Settings, go to the Subscription section and click on the Cancel subscription button. Remember that the cancellation will be effective on the last day of your current plan and by cancelling you tell the system not to renew your payment after that day.