What is the ruling on changing your place after the obligatory prayer to perform the sunnah? The scholars said.

The basic principle is that a person should not mix the regular sunnah with the obligatory prayer so that some people do not get confused, and for that reason the Prophet ﷺ instructed changing the place.

Or waiting to say the adhkar, meaning either separating between the obligatory and the written prayer as the Prophet ﷺ said.

The difference between us and the People of the Book is separating between the obligatory and the voluntary prayers, so you separate them either by time or by place.

Either you sit and say the adhkar, then pray the voluntary prayer, or if you are in a hurry and want to leave, you change your place. This is the sunnah, and this is better.

As for performing the sunnah after the obligatory prayer, it is so that the obligatory prayer is not confused with the sunnah.