Procedure for recycling existing Mod9 CKDas Mod 27s mapped to different SSIDs

Scenario is have existing  set of Mod9 CKDs mapped to ..in reality used as past SRDF R2 targets and C1 C2 sets for DR...total of 9 .

Need to reinvent as a set of Mod27s mapped to  new CU targets.

Would  z/os admins unmap/delete originals and start from scratch or attempt a recycle / expansion of the Mod9s into Mod27s ?

Folk might deduce that question coming from an occasional z/os storage admin...familiar with open system vmax but less so on z/os..

Storage is vmax20k.

No srdf or Timefinder relationships currently in place.

Any suggestions to procdure appreciated.