Theyd probably expect you to let them know in advance though or to have a pattern of weeks you miss. Thats how it was when I did WW. I couldnt just miss random weeks and put it down to shifts, I always told her the week before and she could see a pattern emerging
I put down that I do shifts, but as I was just starting my new job I had no idea what the pattern would be.
Now I do know I will have to stop going to the Monday night meeting and go on a Thursday morning, but can only go every other week, will that be ok do you reckon?