Call to withdraw your resignation.

I think we should take the route of employee care when recalling employees who have left. You can say this:

Hello, XXX, I'm from XXX company. You used to work in our company. What are you doing now?

Waiting for the other party to reply,

Then tell him: the company is developing well now and plans to expand its scale. When our personnel department received this recruitment task, we thought it would be better to find some experienced excellent sales talents instead of recruiting all the new people for training, so we thought of recalling our outstanding colleagues in the past. You are a very good colleague. Are you interested in coming back?

Give the other person some time to think about it. I wish you success.