Dear respected Madeline Saathoff,
Good day! Thank you for posting to Microsoft Community. We are happy to help you.
As per your description, firstly, may I know are you using Word desktop client application or Word for web(online)?
Also, may I know does the Word document stored in online location(OneDrive/SharePoint)?
Using Word desktop client application:
If the Word document stored in online cloud location and AutoSave button turn on, you will only see "Save a Copy" button

However, if you turn off AutoSave button, then you will see "Save As" button.

Using Word online:
In case, if you are using Word online (open Word document in Word online app), then you may Download a Copy, then open downloaded Word document in Word desktop client app and use "Save As" feature to Save the file as a template (.dotx).

Please understand that our initial reply may not always immediately resolve the issue. However, with your help and more detailed information, we can work together to find a solution.
Appreciate your patience and understanding and thank you for your time and cooperation.
Sincerely,
Waqas Muhammad