While I do not know for sure whether IRCC will grant a request to reschedule an online interview in place of an already scheduled in-person interview, odds probably lean against it. I have seen no reports indicating what criteria IRCC might consider in deciding whether to grant such a request. The only reasons to offer are YOUR personal reasons, why you cannot attend an in-person interview.
I agree with @lila777 that the faster and probably safer path to being scheduled for the oath would be to appear for the in-person interview as scheduled.
That said, I suspect that showing up for this interview, as scheduled, is not just outside what you have planned for, but is not practical for you. So, if indeed you cannot appear for the interview as scheduled, you will need to REQUEST the interview be rescheduled. While IRCC is fairly flexible in rescheduling events like this, be aware that multiple failures to appear as scheduled can result in the application being deemed abandoned.
When making the request to reschedule, you can, of course, include a request that they conduct the interview online, and explain YOUR reasons, basically explaining why it is too difficult for you to appear in-person, for YOU, in YOUR situation. Not everyone here agrees, but there is a significant probability that being outside Canada in this situation and rescheduling the interview will lead to a significant delay in how long it takes to complete processing your application . . . well, for sure, just rescheduling results in a delay, at the least however long it takes IRCC to set a new date. This can sometimes result in delay far longer than many anticipate. So the only way to avoid delay is to somehow get here and attend the interview as scheduled.
