Assign a Vacation rule while not in vacation

Summary

Assign a Vacation rule while not in vacation

Content

Hello all

I have a doubt that I'm not yet finding anything but must be certain.
What happens if I enable a "Vacation Period Time" and the employee is not actually in vacation.?
I mean I want Manager A to respond as Manager B while Employee C answer the workflow as Manager A.
But if I configure all in vacation rules it goes all to Employee C. How do I workaround it?

Thank you all