Merging Documents

This only works when documents contain tracked changes !!!

As an alternative to using Track Changes you could use the Merged Documents feature
This would be appropriate if you had to send the document to several people at the same time for review, rather than having them all review the document one after the after.
You can use Merge Documents to integrate all the changes into a single document where you can resolve them all at once in a logical way.

select (Tools > Merge Documents)
The Select File to Merge Into Current Document dialog box is displayed which looks like the standard File Open dialog box.
SS
Browse to the relevant document that you want to merge with your original.
Click Open
Repeat these steps for all the different copies that you need to merge.