If Etihad Airways advises you to present the card used for booking, it must be presented while checking into your flight at the commencement of travel. If you, as the credit card holder, are not travelling, a copy of the credit card with an authorisation signed by yourself, should be presented at check-in.
Alternatively, the card or a copy of the card with your signed authorisation can be presented to the nearest Etihad Airways ticketing office at least 24 hours before the flight. This verification is required to ensure a smooth check-in process at the airport and to avoid being refused carriage. Failure to comply will result in the requirement to pay the full ticket cost at the airport or refusal of carriage.