This feature requires permission to be set by the user who's folder you will be opening.
Click the File menu, select Open & Export, and then Other User's Folder...
In the Open Other User's Folder window, type the name of the person who granted you sharing or delegate access permission, or click Name to select from a list.
In the Folder type list, select the folder you want to open.
Note If you have author or editor permission, any items you create while the shared folder is active are stored in the other person's folder.