In terms of Rule 39(1)(g) of the CGST Rules, 2017, an ISD is required to issue an ISD invoice as prescribed in Rule 54(1) indicating that the invoice is issued only for distribution.
Similarly, in terms of Rule 39(1)(h) of the CGST Rules, 2017, an ISD is required to issue a credit note as prescribed in Rule 54(1) for reduction of credit (if already distributed).
(ICAI FAQ PUBLICATION 06-09-2017 -: Input Tax Credit: FAQ NO. 49)