It might be possible to convert Encore RHP format to ENC using ENCORE! program itself.
Convert Encore file format file to Encore musical notation file format.
We found 2 software records in the database related to .rhp to .enc file format conversion.
Microsoft Windows software - convert rhp to enc on Windows
A notation score writer application
Convert from rhp 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 rhp to enc. 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 rhp to enc on OS X
A notation scores writer and music composing software for Mac