We have found one software suitable in our database for this conversion.
Both .pm6 and .pm5 files are documents from Adobe PageMaker, albeit from different versions of the program. So if any program can successfully re-save one to another, it would be PageMaker, although saving from newer format to some older may be a little tricky if it is possible at all.
Updated: October 13, 2016
One of the first desktop publishing programs, introduced in 1985 by Aldus Corporation, initially for the then-new Apple Macintosh and in 1987 for PCs running the then-new Windows 1.0.
It was later bought by Adobe and rebranded Adobe PageMaker. The last version Adobe PageMaker 7 was released in 2001 and in 2004 the product was discontinued and slowly replaced by Adobe InDesign.