in other airline terms like SQ, its called GV2 promotions wherein both passengers must travel on the outward and inward sectors.

I had like that before on SQ ex SIN. The check in agent tried everything to over ride the system, the problem is the check in system wont accept because the other passenger needs to be checked in as well. The supervisor intervened but told me that if I can produce a medical certificate of my friend including the phone number of the doctor who issued such medical certificate, he can override the system then I'm good to go. I ended buying a new ticket, it cannot be upgraded to any fare class.

At least EK has the option to upgrade this fare with additional 50%? ( I will take it if Im the OP)

So , for these kind of promotions, be sure you are willing to take the risk.