To create a duplicate of any document in the WorkCenter Library, right click the document and choose Duplicate Document.

The reason you might want to duplicate a document in the library is that you want to keep the documents existing format, but want to add a few custom lines to it, or make a few programming changes. Also you could eliminate all the text and copy and paste an existing word document into this letter. By doing this, you are able to keep the mail merge fields in the letter and just changing the body text.

See Editing Documents or Programming Documents.