To be clear, domestic First Class fares that are marketed as "Refundable" are generally fully refundable with no fee. While long-haul international business class/Delta One fares (Delta does not have long-haul international First Class), can sometimes have "refundable" fares which carry a fee if you wish to refund. These tend to be focused on certain markets (for example, LHR) and in Delta's case the fee is typically $900 and is found in the fare rules. "CANCELLATIONS - BEFORE DEPARTURE - CHARGE USD 900.00/CAD 900.00 FOR CANCEL/NO-SHOW."