If your site have .dwt files and site is on live server then modifying the site will not affect the pages which are using the .dwt file.
You will have to follow the following steps in order to make changes on the live site. In this case I used index.html file to make changes in the page. Your case can be different like index.html or whatever else.
If you have same .dwt file for multiple pages then you will have to cloak all those pages and those pages must be opened in Dreamweaver during updating the .dwt file. Every file must be saved after changes are made in the .dwt file. If the file is cloaked then changing the dwt file will automatically affect all other pages all you have to do is to save those changes.
1. Download the entire site.
2. Open dream weaver.
3. Click Site -> New Site (give name to the site).
4. Copy all the files either to the folder set in previous step or just drag all the files in to the local files area for the created site. This area is usually on the right side of the Dreamweaver.
5. Now Right click on the file to which .dwt file is linked and you want to modify e.g. we may want to modify index.html.
6. Right Click -> Cloaking
7. Now open .dwt file and index.html file
8. Modify the .dwt file. And save it.
9. It will prompt to update site. Click yes and also save the index.html file.
update dwt file