How can I create different persons with the same national identifier?

We recently encountered a case where a national ID was used by a student before, let's say B12345678. Another student has recently enrolled with the same national ID, B12345678. We suspect that the previous student's national ID was not verified. Now we cannot create the newly enrolled student with national ID B12345678.

We don't want to update the previous student's national ID, as he or she has been inactive for a while. How can we resolve this issue?