Gift Certificates Sent - need to delete two

I've accidentally sent a client a gift certificate twice. When I enter the Gift Certificates Sent in Gift Certificates/Coupons, it lists them both but there is no way to delete one of them. How can I do this?

You can either login as your test customer and redeem them yourself or via phpMyAdmin edit the table:
coupon

and mark them as:
coupon_active

and set that to X

I use X to indicate that I have canceled them and that they were never redeemed ...

If they were different certificates you can delete one in
admin > gift > coupon admin

If you sent the same one twice there is nothing that you can do as it is already sent

Or what Ajeh stated

I looked in myphpadmin coupon table and also the coupon_gv_customer and can't find the customers id who I need to delete a gift certificate from. The GV was sent to her instead of her gift recipient so I need to remove it but can't follow the answers already provided. Thank you for any help!

Never mind...I figured it out! Sorry to have bothered anyone but I figured out that the coupon section had ALL of the coupons and gift certificates mixed together. Thank you anyways!