Being a hairdresser by trade and having lost customers in the past - I would only say whatever happens be up front and just say you are changing , maybe as you want to be pampered in the shop is a good one - I used to do Erin`s god mother and now don`t but we are still best of friends - so it can but help to say

I did one lady for 9 years every Christmas eve even if it was a Sunday and she just said I don`t want it done next month out of the blue and that hurt
I hope you find answers somehow
Suzanne x