UltraEdit does not detect changes in the wordfile which are done outside UltraEdit. But it automatically rereads the wordfile if the changes are done within current instance of UltraEdit.

So after you have modified your wordfile with the Python script, you have to open your modified wordfile in UltraEdit, make a temporary modification (insert a space and delete it immediately with backspace) and save it and close the wordfile. Assuming you run the Python script via an UltraEdit user tool, the following macro would do this:

InsertMode
ColumnModeOff
HexOff
RunTool "Case sensitive name of the python script running tool"
Open "Name of your wordfile with full path"
" "
Key BACKSPACE
CloseFile Save

Disadvantage of this solution: the wordfile will be added to the list of recently used files.