I appreciate that it is normally not possible to change the name of a ticket holder, but would it be possible to change the name of the ticket holder for an open ticket that was converted following a cancellation from Turkish Airlines?

I had two trips planned with a friend (April and October this year) and both have been cancelled by TK. The destinations are both best in either October or April, so we would ideally travel to one place in October and the other in April next year. However, as open ticket validity ends on 31 March and my friend does not have enough holidays to take both trips this year, it would be great if it was possible to change the name from my friend to my girlfriend in order to have both trips in October/November this year. Does anybody know whether this is possible?

The ticket we would like to change the name on was purchased during the 40 % off campaign in January, so it is not an option to cancel and rebook (without incurring substantial additional fees).