What style is your document now in?  

To change styles in word use the pulldown menu "Style" to select anouther style.  Scan through the list of available bibliographic styles and select one to change the format of your document in-text citations and bibliography.

Did the style of your document change?  If not, click on the "Update Citations and Bibliography" button.

To updated a reference in EndNote that is already included in your document.

Go to EndNote, and edit the title of one of the references you are using in your document.  Look at the Word document again.  The title has not changed yet.

Click on the UPDATE CITATIONS & BIBLIOGRAPHY button. The citation should update in the document to reflect the changes you made in EndNote.