Dear Lalitha,
Carefully going through your predicament, on rejoining employee(s) after his/their resignation. I have the following remarks and recommendations:
1. Your employee, has tendered his resignation and duly approved by the management. It is understood that all legal protocols have been observed. All parties are free from legal obstacle. Since, the finance and operations department's assignments were done.
2. Refer to your manual, re: rejoining of employee..... do you have any policy on this matter? If yes, you don't have anything to do but just apply it. If none, then you can not act alone at your own volition. Hence, you need to formulate a policy that deals on this matter and approved it by the management. For the meantime, the employee must wait.
3. Assuming that you don't have policy on this matter. Always put in your mind the safest way is follow the law so as not to compromise the employee much the employer, especially, you don't have existing policy on this matter and you can not predict the consequences in the future.
4. When the employee resigned... and approved by the management..... that terminated the relations of the employer and the employee, except, the monetary obligations that a unilateral action by the employee to collect is required. Therefore, should the employee wishes to join the company (again). The employee should go through the normal procedure of applying and follow the stages of your recruitment policy. He wil join as new employee.
5. As you mentioned, the employee was the one setting the conditions of his coming back. This situation, you are unaware that the employee is digging hard to put himself in a solid ground, this is a very treacherous legal maneuvering which is prejudicial to the interest of the management.
6. Stay on the safest road, no policy of rejoining, create a policy. Put away the company and the employee for any future legal arguments.
Best wishes.
Dr. Dionicio D. Viloria, SPHR
Sultanate of Oman