1) Create and Export from the existing installation within the PMAdmin site | general settings | import/export (save export Password)
2) Uninstall Password Manager from add/remove programs
3) Install 5.9.x from the installation media.
4) Launch PMAdmin site and select unique instance of Password Manager
5) Import the settings from step 1 within the PMAdmin site | general settings | import/export
Please note: Additional solutions are available on upgrading as well has creating an export file if more detailed information is required.