If you requested a withdrawal but changed your mind, you can cancel it at any time, as long as it has not been processed or the payment has not been confirmed.
Here is an article on how to check a withdrawal status : Where can I check withdrawal status and history?
If your withdrawal request is Pending, it can be canceled by selecting the CANCEL option next to it, so the money will return back to the player account balance.
If your withdrawal request is Confirmed, the withdrawal can no longer be canceled.