Internal transfer for articling students?

Hello! I was looking for some insight as to how easy/common it may be for a summer student, who’s expected to return as an articling student, to transfer from one office to another to complete their articles.

I’m looking to participate in the 2L Calgary recruit but have started considering to article in Toronto (my partner is currently articling there). The current goal is a larger corporate/commercial leaning firm in Calgary.

If office-office transfer isn’t possible, is the Toronto articling recruit my only other option pre-call to the bar?