What is the expiation for a permissible vow?

Question:
I am a teacher, and I told my fellow teachers that if I am transferred from this school, I will slaughter a sacrificial animal. I meant that I would be relieved of the principal.

Answer:
I mean, I am a teacher, and I told my fellow teachers that if I am transferred from this school, I will slaughter a sacrificial animal. I meant that I would be relieved of the principal. I meant to be relieved of the principal, because the school principal is harsh with us. Then I was transferred from the school, and the principal was transferred as well. So in this case, am I required to slaughter the animal or not? I mean, I was transferred with her, so I did not get what I intended. The intended outcome did not happen.
As for the case where you were transferred to another place, this is a permissible vow. If you wish, you may fulfill it; if you wish, you may expiate it as an oath expiation, which is a choice. A permissible vow allows one to choose between fulfilling it and paying the expiation for an oath. Yes.