Here is a summary of the steps on how to cancel a request via Request Money:
STEP 1: On your GCash homepage, tap Send.
STEP 2: Tap Request Money.
STEP 3: Under the Requests Sent tab, tap on the profile of the person you requested money from.
STEP 4: Tap Delete
STEP 5: Tap Proceed
You will receive a pop-up notification that your Request Money was deleted.