Rule 89 says-
Provided further that in respect of supplies to a Special Economic Zone unit or a Special Economic Zone developer, the application for refund shall be filed by the –
(a) supplier of goods after such goods have been admitted in full in the Special Economic Zone for authorised operations, as endorsed by the specified officer of the Zone;
(b) supplier of services along with such evidence regarding receipt of services for authorised operations as endorsed by the specified officer of the Zone:
Thus in case of SEZ, endorsement by specified officer of the zone is required to claim refund.
Specified officer of SEZ means Govt. officer of SEZ.