[susan53]

You said : another ...doubt.
If in the question there is a tense I had better use it also in the reply, had I not? Or I can change if I prefer?

Example:

A: Have you seen the doctor recently?
B: Yep, I met him yesterday.

No, you don't have to use the same verb form at all. It's the same as I said in the message above. Grammar expresses meaning, and the verb form you choose depends on what meaning you want to express.

Here, A chooses the present perfect because she is talking abour indefinite past time - that is, any time up to the present moment: Have you seen the Doctor?

However, B's reply specifies an action in past time : "yesterday". So the past simple must be used : I met him yesterday.

Here's another example. This time A asks about the past, but B replies about the future - so obviously the verb form changes - because the "meaning" of the two speakers is quite different :

A : Did you see the doctor yesterday?
B : No - I'm seeing her tomorrow.