Deletes a plan

        :param plan: Plan to delete
        :raises: FBchatException if request failed

def deletePlan(self, plan):
        """
        Deletes a plan

        :param plan: Plan to delete
        :raises: FBchatException if request failed
        """
        data = {"event_reminder_id": plan.uid, "delete": "true", "acontext": ACONTEXT}
        j = self._post(self.req_url.PLAN_CHANGE, data, fix_request=True, as_json=True)