During the interview. Candidates don't know which examination room they are or who their interviewer is before the interview, but the interviewer draws lots temporarily on the day of the interview, which is random, so it is impossible for candidates to know who their interviewer is, their examination room and test number, and the interviewer doesn't know the candidates' information in this examination room before the interview, so neither of them can know the interview information in advance.
Candidates cannot reveal their basic information during the interview. Once personal information is disclosed, it will be treated as cheating and the interview qualification will be cancelled, so there is no need to find a relationship in the interview.