Transfering a sequential dataset to an existing GDG file overriding the lastest existing GDG version cannot be achieved using the relative naming convention, the WFNAME is expected and a rename will be attempted to create a new version.

If the need is to receive in version 0 of the GDG (the already existing last version) it should be managed by the JCL end of transfer procedure.

For example:

The name of GDG(+0) can be transmitted to the receiver in the PARM parameter. You can use one CFTRECV with a reception sequential file.
In the end of transfer JCL, you can use the copy &FNAME to &PARM.