Does anyone know what happens to your pay grid when you change school boards?

I have a PDF that states your previous seniority may be used for grid placement for LTO pay, but nothing about once you become a full-time teacher in the new board.

My assumption is it stays the same, but I have not been able to find a source to answer this.

example-

A4 + 'grid year 4' in school board A for 2020 would be A4 'grid year _____' in school board B for 2021

Thanks.