It's happened a few times that my supervisor or my boss has told me that there's something that they're going to assign to me but nothing happens. For one of them, my boss said that the prerequisites were not ready yet. But I have no idea what the reasons were for the others.
I'd like to know what the best way is to follow up with them about those tasks. I don't know what politics to use when asking them that what happened to that X task that I was supposed to do; so that they don't think that I'm going to judge their weak schedule or question their wrong information. On the other hand, I'm afraid if I don't ask anything they'll think that I'm not interested in doing tasks and prefer to be idle at work.
To clarify my question I need to add that my role is DB report writer. So I need to wait for a report to be requested by some other departments to do that. Besides, the prerequisites also should be prepared by other departments. I have told my boss that I have sometime among my reports to do something else but he had no idea what to assign to me. I have defined a project for myself and told my boss that I'm going to investigate on something to see if that helps part of their job.