If you've already agreed to join but don't want to go, you can honestly explain to the employer that you've changed your mind and notify them in advance so they have time to find a replacement. Here are some suggested phrases:
1.Honest communication: Be honest with your employer about your idea and that you have changed your mind and are not planning to come to work.
2.Sincere Apology: Sincerely apologize to the employer for the inconvenience caused, explain the situation, and apologize.
3.Advance notice: Try to give your employer as far advance notice as possible to give them enough time to find a suitable candidate again.
4.Be polite: Be polite and respectful during the rejection process, and don't cause unnecessary distress and hardship to the employer.
Sample phrase: I'm very sorry, I changed my career plan and don't plan to take the job. I'm really sorry for the inconvenience, and thank you for your understanding and understanding. "
I suddenly changed my career development plan and decided not to accept this job, and I am very sorry. I hope to let you know as soon as possible so that you have plenty of time to find other suitable candidates. "
After careful consideration, I have decided not to work at your company, and I am sorry for the trouble. Thank you very much for your understanding and apologize again. "