Problem

The user submitting a change request can also review the request. When doing so, their options are to Comment or Close, which is appropriate.

However, it isn't sufficiently obvious that the Approve and Request changes aren't possible because the option can be chosen by clicking on the text (good!) and the text is the same in appearance as the other options — only the radio buttons are changed in appearance.

Solution

Grey out the Approve and Request changes options to make it more clear those are unselectable. The grey of "Preview" on the unselected Preview tab would work.