The manager of the naked resignation unit who used to be unhappy suddenly called you and asked if you were at work. What do you mean? How should I reply?

Maybe he wants you to go back to work. Maybe he just wants to know how you are. If you want to go back and continue to work there, then you can tell him that's the case and see if he has any further comments. But I think if it was unpleasant before, it is estimated that you will not get along well when you go back this time, so you must think about it. If you think he may try to laugh at you or other ideas. Then you can talk about yourself better.