Can I update/modify my card details?

This depends on what you're trying to update/modify. If it's the registered address or email, then yes it is possible. However, name modification would not be possible. Especially for generic gift cards. Generic gift cards are cards that have the following name registered to them:

THANK YOU MERCI
VALUED CARDHOLDER

Or any variations of the above. Any name change request for these types of cards will not be legally possible.

The only situation where a name change may be considered is if the card is registered to your personal name, such as John Doe. That said, you will still need to forward your request to the company/organization that originally issued you the card as they will need to make such a request on your behalf. The only profile changes/modifications that we are able to entertain are for:

Addresses
Registered email