I work on a small team and only a few can be off at any one time. As soon as the holiday booking period opened in January I booked next week off as for 4 days leave you get 10 days off. Others also booked up too to the max allowed off. I don’t want that leave now as my plans have changed. My colleague is grumbling as they are saying they would have booked a holiday if they could have had the leave but I got in first. He complained to our manager who says I can’t cancel as such short notice. Is this allowed?