Individual sessions are non-refundable.
You can change a booking, if you make the change no later than 48 hours prior to the original booking. Such a rebooking can be made in the following 15 days . You can only rebook once. Unused sessions which have not been rebooked in the above way will be void. Cancellations and rebookings made less than 48 hours prior to a booked session will be considered unused and void.
Remember that unused sessions (incl. no-show) are not refundable.