["I had an unexpected emergency pop up and I couldn't make it in to cover him.I felt really bad for not being able to cover him.", 'Did he get mad at you?', 'Yeah he was really frustrated with me. I really hope he forgives me, and lets me make it up to him.']
Buy him something sweet, like a chocolate cake, it usually helps.
I felt really bad because I told Kevin I would cover his shift, but I was unable to.