If the renter needs to cancel a booking after the payment has been done, the renter must compensate the owner for a percentage of the booking sum, as stated in the Article "Cancellation" in the rental agreement (unless mutually agreed on otherwise between the renter and the owner).
If the owner wants to (partially) refund the renter as a friendly gesture, the booking can stay as it is (the owner will thus receive the his or her earnings at the end of the rental period). The amount that owner and renter agree to be refunded to the renter can be settled outside of the Gearbooker platform.