Since you have received a gift card from Dansk Folkehjælp, it is intended to be used within a specific timeframe, which is stated in the email you received with the gift card. If you do not manage to use it within this period, it cannot be extended.
Once you have redeemed your gift card from Dansk Folkehjælp, you will receive a new gift card (e.g. for H&M) with a different expiration date. This expiration date will be shown at the bottom of your new gift card as well as in your order confirmation.