I would have thought a Rest Day is a 'Day Off' in which It cannot be changed just like that without notice,
But you maybe thinking your 'rest day' means that you are actually on what is known as ''Available''.
IE: you are not on standby, so you do not have to be contactable, nor answer the phone on that day, but you can be rostered a flight beforehand or used for something - I am not sure what happens if you answer the phone on an available day and then say no, I do not think you can say no in that case, but I am not fully up to speed with latest rules.
''Available day'' does not count as duty hours unless they use you.
BTW are you FD or CC? - from your previous posts you seem to be FD crew, but this has been posted in the CC forum...
Edit - You mention that 'after your duty week ends your planned rest day has now been rostered for a duty' - Therefore that seems to me they have now rostered you without notice to fly on your first day off after your roster...That does not sound kosher to me. Or was your planned rest day annual leave?
I think you need to clarify with your LM your actual roster terminology, your days off entitlement, and find out what is the case here...
Last edited by rog747; 14th Sep 2018 at 11:59.