I was confronted last night by my supervisor about my hours and availability.I hired on with the understanding that I would be working 4-5 hours a night. Management was willing to work with my hours of availability. I have 6 months of service in and in that 6 months of service I have worked all kinds of hours. I work in the Next Day Air building. I have 4 children under the age of 14. My husband works 3rd shift and needs to leave for his job by 10:15 pm. I work 45 minutes away from where I live, I need to leave work by 9:30pm. I started out being an unloader, we were done by 9:30pm. An opening came up in the air building and I was asked if I was interested. I said yes and I told them what my situation was and they were willing to work with me. I have been doing this for the past 6 months, no questions asked. Last night I was confronted by my supervisor saying that I can no longer leave by this time because I am leaving before other employees with more seniority and they can file a grievance against the supervisor. Why all of a sudden has this changed? I was wondering what other people have to say about this and what are some of my options on what I can do.