I have posted this before, but I will post it again.
Changing unions does not give a new union the right to negotiate a new CBA unless Section 6 Negotiations are scheduled.
They cannot come in and change an exsisting CBA, they inherit the current CBA from the previous union, grievance awards and arbitrations also cannot be changed.
Examples, AMFA replaces IAM at UA, NW and IBT at WN, AMFA inherits IAM and IBT CBA and by law has to enforce them and does not negotiate a new CBA until Section 6.
PFAA replaces the IBT at NW and then AFA replaces PFAA, read above, same results.
IAM replaces TWU at HP, IAM replaces IBT at HP, read above again.
Don't let the facts get in your way.