It isn't. In English we do not have this kind of flexibility in question forms. Only the first question is correct.
I can see from your question that you haven't been taught the basic formula for interrogative forms. This is the standard word order:
1. Question word: When
2. Auxiliary verb: was
3. Subject: the reservation
4. Main verb: made?
This is a very simple formula, and it works for all types of questions. You need to learn this 1,2,3, 4 formula and use it whenever you make a question.