No,you will receive different admit cards for both january and april exam sessions and so your exam centres can also change.You will the asked the centre of preferences again for your april session and then you can give the same places and chances are there that you might get the same centre.JEE Main 2020 Admit Card Availability for April 2020 Session will be from 16 march 2020

Dear Aspirant

No ,centre can be change or not ,it depends upon when you will fill form and it also depend upon preference of examination centre filled by candidates.

Application number for both the JEE Main (Jan and Apr) remains same.

But the Roll numbers that are allotted after the admit cards are out are different for both the exams.

When you will register for JEE Main April exam, you will have to use the same application number as that of January (for those who have registered for Jan exam).

Those who have not registered for Jan exam and wish to appear for Apr exam, they will have to register themselves during the registration window (For April session). Such candidates will get a new Application number.

Thanks

All the very best