My employer has just announced that all staff can have 2 extra days paid leave over Christmas. The days are fixed, we can’t take them another time. I work part time and one of the leave days falls on my normal day off. AIBU to ask for an extra portion of a day off (I would be asking for half a day beforehand) so I get the same as everyone else (1.6 days total as I work 80% hours) or is that being really petty?