Both .pm4 and .p65 files are from Adobe PageMaker and if any program can somehow work with them, or convert them, it would be it. However, it seems like files used in different versions of the program, so you may need a specific version of PageMaker in order to convert the files or somehow resave these two files.
Convert Adobe Pagemaker 4 document to Adobe PageMaker 6.5 document.
We have found 2 software records in our database eligible for .pm4 to .p65 file format conversion.
Microsoft Windows software - convert pm4 to p65 on Windows
One of the first desktop publishing programs on market
Convert from pm4 file format
The tables with software actions are a good pointer for what a certain program does with various file types and often may give users a good hint how to perform certain file conversion, for example the above-mentioned pm4 to p65. However, it is not perfect and sometimes can show results which are not really usable because of how certain programs work with files and the possible conversion is thus actually not possible at all.
Apple macOS / Mac OS X software - convert pm4 to p65 on OS X
Mac version of once popular publishing program