RDA 3.4
From AC Wiki
STEP 3.4 : CMC to GMD
cmc to gmd
If you are choosing to have the RDA processes upgrade your existing RDA bib records, MARS 2.0 provides the option to add a GMD in the 245 $h if it is missing in order to create a hybrid AACR2/RDA record.
While PCC guidelines suggest GMD and CMC can co-exist in the same record, it does not recommend adding a GMD to an existing RDA bib record.
LINKS
1.0 - 2.0 - 3.0 - 4.0 - 5.0 - 6.0