Article 37 of the Labor Contract Law stipulates that employees only need to notify the unit in writing 30 days in advance to terminate their labor relations (resignation). If you are still on probation, you only need to give a written notice 3 days in advance.

Therefore, leaving your job is the right given to you by law, and the unit leader has no right to "approve"!

So:

If it is the unit leader who goes back on his word: he has no right to go back on his word! You can still leave your job.

If you go back on your word: sorry, there is no regret medicine in the world ... you can only negotiate with the company to see if they are willing to keep you.

I hope I can help you!