Apologies, that was not clear to me from the way you phrased your original question.

I've already used mine, but in looking at My Wallet they still show up even though used/closed. They are listed as "Partially Transferable" and from the pop-up text "The passenger that is named on the certificate/ecredit needs to be traveling in the same reservation to transfer."

The T&C further say that "The Delta eCerts Credit Voucher may be combined with up to four other Delta eCerts Credit Vouchers (for a maximum of five) for Certificates beginning with 006068XXXXXXX or 006069XXXXXXX, provided the person to whom each certificate is issued is traveling in the same reservation when redeemed via Delta channels."

And the voucher does begin with 006068 and was issued in my name. So I suspect there is no workaround to be had here, the system will likely enforce it at booking time. But I have not had any trouble using it for myself, so I have no firsthand experience, perhaps someone else can speak to that...