How to create a PF without loosing the data in SYNON?

By changing the below model values we can achieve this:

YOLDLIB - Name of the library into which you want old physical files archived.
YCPYLIB - Name of the library from which you want physical file data copied during the generation process.

Normally these two model values are the same because you store data in an archive library and then copy the data back from the same library.

Firstly create an archive library for this process (I refer to this as arc-lib):
CRTLIB LIB(arc-lib) TYPE(*TEST) TEXT('Archive library for my model')

Secondly Change the model values YOLDLIB and YCPYLIB to be arc-lib:
YCHGMDLVAL MDLVAL(YOLDLIB) VALUE(arc-lib)
YCHGMDLVAL MDLVAL(YCPYLIB) VALUE(arc-lib)

Thirdly Use YEDTLIBLST to edit your model's interactive and batch JOBD library lists to include arc-lib.

Now we are all set to recompile the PF without loosing the data.