Normally all documents in a project are generated from the same (empty) word document.
You may want sometime to use a different format (ex: a A3 or Tabloid format for a big traceability table)
If you have the Label/Variant module, you can easily do it using some "Status based document templates". More info in Word Templates explanation..
You have to go in the administration > Projects > ProjectName > Project Settings > Word / PDF Styling and you can create a dedicated template when specific labels are used.
For example: to apply an obsolete template to the downloaded documents: