Not changing names works to your benefit, I promise you. If you could change names, travel companies would buy up all the tickets and then sell them on to you at inflated prices, changing the name at that point.

Can you separate the two of you onto different flights on different days? You could therefore both go to wherever you are going but separately, each of you taking a friend who could book their own ticket.

If you cancel, assuming its long-haul, you'd get the taxes back (and fuel surcharge?) which would be around £150 per ticket (£300+ with the fuel surcharge).