If the item was created in mailbox A and you want to save it in the Drafts folder of mailbox B you can do so if you have the necessary permissions. You will also need to have the alternate mailbox opened as part of your Outlook
profile. If mailbox B is opened as part of your profile you can iterate the Stores collection of the NameSpace object until you find the Store for mailbox B, then get the Store.Folders collection and get the Drafts folder in that store. Then you can call the
Move() function on the existing item to move it to the mailbox B Drafts folder.