Question

A friend of mine asked me the following question:

He studies medicine at Soroka, is in his fifth year, and they have residency rotations in different hospitals. The starting point for many of the students is Be’er Sheva itself, so a rotation at Soroka is preferred.

He was assigned a two-week rotation at Assuta Ashdod, which is a bummer for him because it means commuting during the rotation for about two hours each way.
A fellow student who was assigned to Assuta Ramat HaHayal was happy to swap with him—and for him Ramat HaHayal was far preferable, since his parents’ home (he is single) is in Bnei Brak. For her it was preferable because she lives in Be’er Sheva.

All this was about a month and a half ago, around the beginning of the semester.

Now they announced that everyone who was assigned to Ramat HaHayal will ultimately do the rotation at Soroka instead (because of system considerations).

She most likely prefers Soroka and not Ashdod. (Though in the meantime she has not approached him to ask to switch back.) It is just that initially she preferred Ashdod over Ramat HaHayal.

For my friend, Ramat HaHayal and Soroka are equally preferable (he either has an apartment in Be’er Sheva or can stay with his parents as above).

The question: from a halakhic standpoint, whose right is it—his or hers? In terms of ownership, acquisition, and so on?
And what about from the moral standpoint?

Thank you very much!