As long as your request hasn't been approved, you can cancel the request.

First, next to the Update Activity button, click on the Oval Icon containing three dots and click Cancel Request. 

A Cancel Request pop-up window will come up. The submitter will be required to enter comments and click Confirm.

By clicking Confirm in the Cancel Request pop-up window, the system will:  

• Change the Request status to Canceled. 
• Send an email to the current and any previous Approver(s) notifying them that the request has been canceled. 

Note: Once the request is Canceled, it cannot be restored.