Yes, you can change your RD number in the CET application. Here are simple points:
The CET authority gives a correction window for making changes in your form.
During this time, you can edit or update your RD number online.
This is useful if there was a mistake or missing RD number in your first submission.
Only changes done during the official correction dates will be accepted.
No changes are allowed after the deadline, so act on time.
The correction is done through the official CET website, not offline.
Make sure your new RD number is correct and valid before submitting.