Do you have the right to ask a manager to give you a reason for calling you in to have a private meeting?
An assistant manager told me to be in my manager's office on a certain day and time. This individual also told me that the workday I picked up from someone else will be covered by another person. I have asked whether there is a reason my days have been cut and why the day I picked up from someone was taken away, but the only thing I was told is to meet with the manger on the set day and time. Human resources told me the same thing. Am I in the right for requesting an answer before the meeting, since my day of work was taken away from me?
You can always ask why; but the real question I think is whether management is required to respond to your query in order to require your cooperation. And unless you are covered under a union contract that specifies differently, the answer to that question is: No, it is not.
That is, management has a right to demand your cooperation regarding a meeting at any time for any reason during hours for which you are being paid your normal rate. Management is not required to provide you with a reason for taking away your hours or for your attendance at a meeting.
Good management practices might indicate that it SHOULD tell you why your hours were given to someone else and the reason you are being told to report to a private meeting. But your question pertained to rights, and management is not required to do either of these things.