In D365 F&O for HR and Leave & Absence modules, we have the functionality to buy and sell leave requests.

The user can buy a leave or sell a leave from a pre-defined balance. But there is no option to cancel the bought or sold requests. Once the leaves are bought or sold, it's final and the balance changes permanently.

Since there is a functionality to cancel time off/leave requests in the regular leaves, there should be an option to cancel the Bought/Sold Leave requests also.