Where I work we have had a member of staff retire this means that there are 2 shifts needing covering every weekend I already work the Saturday. We’ve all been made to pick up an extra 2 shifts a month so I would end up working 2 Sundays a month meaning I only get 2 weekend days off fully. I’ve only been made aware of the changes last week but have said I am limited to the shifts I can cover due to pre arranged plans on Sundays as it’s my only day off. I’ve said I’m ok to work some Sundays but not as many as they want me to. My work contract states my hours and mentions being flexible with shifts or something along those lines but I assumed and was led to believe it meant covering sickness and the odd holiday. Do i have any rights can I refuse. I don’t want to make my collage’s take on all the shifts but Sunday is also the only day spent with my partner.