The Update PFILE 2 command updates one or more LF source type (not LF38)
members to change the PFILE keyword to a library qualified value. This allows
the source to be changed to indicate that the LF should be built over a PF in a
specific library. If the existing physical file is on the library list,
attempting to create the new logical file over a copy of the physical can often
result in the logical being built over the wrong physical file.