How to proceed when my J1 visa interview date is beyond the start date of my post-doc program in USA?

My DS2019 is on its way to reach me in India. My podt-doc program starts on 1st march 2023. despite best efforts, if the interview date happens beyond my program start date, what steps should i take up with the university or with the US VISA department?

You will need to differ the start date so that it is after your interview. The university can issue an updated DS-2019 showing the new start date that you will need to carry to your interview.

Will the SEVIS no already shown in the one i hold change? Or with the SEVIS no a new start date appears? In DS 160 while submitting the current sevis no and program code is given and this query in this context. Will be very grateful if there is an answer to it.

SEVIS once issued wont change.

Thanks a lot for the answers. I have one moreā€¦
Do I , as a J1 visa applicant, have to pay reciprocity fee after VISA approval? hwo much is that?