This is the first time I've heard about these in-person COPRs (interviews?)! I don't suppose you guys know what the deal is with this interview? I made an inland application with my spouse as my dependant when we were both in Canada on work permits. They've since expired, I have an application in for a new work permit (currently on implied status) but because my NOC is only C, my partner wasn't eligible to apply for a new work permit. He's having to go back to the UK in the meantime, this won't be an issue will it?
Some get PPR requests and some get an approval letter inviting them to attend either Halifax or Fredericton visa offices to complete the COPR process. If your partner needs to go back to the UK then when they re land in Canada they will complete the process at the airport. So long as you notify IRCC that they have returned back to the uk it won’t be a problem. My WP expires at the end of April, my wife and kids are on visitor visas linked to my WP. How soon before your expiry date did you apply