I just received a notice that the schedule was changed to where I was off and now I have to work, to my understanding because a coworker was fired, my issue is that I was not scheduled today and I had made plans for myself and I was not asked if I could come in before these changes were made, the same thing happened yesterday as well and I was notified while I was sleeping at 1am in which I received the notification when I woke up, both times no one asked if I was available to come in and yesterday I had plans that I had pushed to today in which I was still not scheduled to work, when it comes down to it the question is

Can I be rescheduled to work by my employer without any notice nor any confirmation or conversation between us about wither I was available or not to work 5 hours before the shift starts?