A refund for a Pearl card works exactly the same as a manual refund for a Bracelet. 

Manual refund for onsite Top Up with Credit/Debit card or cash

This applies to Bracelets or Pearl cards that only have been topped up onsite at Tomorrowland Winter with cash or credit/debit card. You have to fill out a manual refund form. Please note that you are responsible for providing Tomorrowland with the correct information.
 A refund fee of 1,5 ‘Pearls’ applies.