The document has to have the attribute changeable or, if you are the author, changeable by author. In the private folder area, this attribute only applies after the document has been sent. You can define a default setting for this attribute in your private office settings. You can only change a document that is not changeable by making a copy of the document and making the changes to the copy.

In order to change a document that is located in a shared folder, you require the corresponding folder access authorization.

Proceed as described in Displaying and Changing a Document.