On verification of FORM GSTR-2A, if the recipient finds that certain inward supplies made by him are not reflected, can he add the details of such inward supplies manually?

If the recipient finds that certain inward supplies made to him in the tax period are not reflected in the FORM GSTR-2A, the recipient can manually add the details of such supplies in FORM GSTR-2. Such additions will be communicated to the supplier in FORM GSTR-1A. The supplier can accept/reject such modifications before 17th of the succeeding period, upon which, FORM GSTR-1 filed by him would stand amended.

(ICAI FAQ PUBLICATION 06-09-2017 -: Returns : FAQ NO. 7)