How to use "save as" command in AppleScript with MS Word - ms-word

Question

I want to convert MS Word document (docx) to PDF with AppleScript.
I tried the code below with Script Editor.
(MS Word document is opened beforehand.)
tell application "Microsoft Word"
activate
set outpath to "Documents/test.pdf"
set activeDoc to active document
save as activeDoc file name outpath file format format PDF
end tell
and failed with the error:
The active document doesn't understand "save as" message.
number -1708 from active document
Versions
macOS Mojave 10.14.4
Microsoft Word for Mac 16.27 (19071500)
Script Editor 2.11 (203.1), Apple Script 2.7
With PowerPoint
The code below worked. It successfully saved test.pdf under ~/Library/Containers/com.microsoft.Powerpoint/Data/Documents.
set outpath to "Documents/test.pdf"
tell application "Microsoft PowerPoint"
activate
save active presentation in outpath as save as PDF
end tell

Answer 1

outpath is invalid anyway and it must be an HFS path
set outpath to (path to documents folder as text) & "test.pdf"
tell application "Microsoft Word"
activate
set activeDoc to active document
save as activeDoc file name outpath file format format PDF
end tell