If you just need to update a document in UMContent (and you do not need the previous version out on the web and you do not need to change the text), you can use these steps to update your document. The advantage to updating your document this way is that you do not have to go through the process of creating a new link and checking in a new document.
1) Log in to the UMContent server.
2) Search for the document you want to update in the content server.
3) Enter information for the search. I typically use the Author field and for Web Site Object Type I have all my documents set as Other.
4) Select the first icon under Actions. Then under the menu select Check Out.
5) Select the Check In button.
6) Under the Primary File field, browse for your document and locate it on your computer and select it.
7) Select Check In. After this step it should be loaded in the content server.
8) Select Content Info which is located next to the Content ID. By going into Content Info you can verify that your document has been uploaded.
9) You will see the Native File is now the new document you just checked in and it is now revision 2. If you want to go back to the previous document you can delete revision 2 (under Actions).