Do i hv to go through the entire procedure of the initial issue
You sure you are a CFI?
It's not that hard to find the correct regulation 61.197 and 61.199
[Reinstatement requirements of an expired flight instructor certificate.]
[(a) Flight instructor certificates. The holder of an expired flight instructor certificate who has not complied with the flight instructor renewal requirements of Sec. 61.197 may reinstate that flight instructor certificate and ratings by filing a completed and signed application with the FAA and satisfactorily completing one of the following reinstatement requirements:
(1) A flight instructor certification practical test, as prescribed by Sec. 61.183(h), for one of the ratings held on the expired flight instructor certificate.
(2) A flight instructor certification practical test for an additional rating.