You can check your pre-booked pass via MyDigi App by click on the Prebook tab at your MyDigi app homepage. Refer to below step to cancel your pre-booked Roaming pass.

Step 1: In MyDigi app homepage, navigate to Prebook tab

Step 2: Click on 'Cancel My Pass' 

Step 3: Select 'Yes'

Note: You can cancel the pre-booked Roaming Pass as long as it has not been activated yet.