Dear Amit,
As Mr. Sadashiv Rao said, there is no form required to be submitted with ESIC authorities upon the relieving of a person who is covered under the ESI scheme.
In the Half-year return "Return of Contribution" Form No. 6, there is a Col. No. 7A which states, "Whether still continues working & drawing wages within the insurable wage ceiling." Under this column, you have to mention "NO." Additionally, under Column 8 of Form No. 6, under "Remarks," you are required to declare the "Date of Leaving" of the employee.
The information as declared by the employer in Form 6 regarding the leaving of insurable employment by an employee will be forwarded by the Local ESIC office to the concerned ESI dispensary for necessary updates.
Regards, Anil Anand