You can cancel your previously made reUse request by going to the ReUse requests section.
By using the reUse overview filter you can easily search for a particular request, or you might already see the request in the main overview screen.
When you have found the request you like to cancel, hover with the mouse over the green button on the right and select "Cancel re-use"
Also in the detail screen of your particular request, you have the option to cancel a request as shown below.
You can provide a cancellation reason (for later reference) and click on Save, to complete the action