In version 6.11 of confluence the "edit i office" button was removed from the attachments view of a page. The "edit in office" button made it very easy for people for edit attachments, now you have to download/upload an attachment in order to edit it (and in the meantime remember to lock it). 

The edit button is only available on the "preview" page for an attachment. I suggest adding a "Preview" button to the attachment list, making it easier for people to edit the attachment (click "preview" then click "edit").

Actually the attachments macro already supports this by having a "preview" button in the list. All you need to do is to add the same preview button to the pages attachments view.