It gets entered in the records as an outstanding certificate. A signed certificate is mailed either to you or directly to the recipient. It will specify who it is a gift from and what it is for. The recipient makes all arrangements for the class, climb, or other event directly. They redeem the certificate, at which point a signed copy is surrendered and it is entered in the records as closed.
Redemption can be for down-payment, a balance due, or full payment as appropriate.
In general gift certificates are not redeemable forcash by the recipient or the purchasing party. In general the recipient cannot transfer the certificate to another party, nor can they use it outside of what it was specified for. However, I will contact the purchaser and allow them to decide this if it is requested.