You can't login twice at time but you can disconnect and reconnect. If you connected via connect a network share, you should be able to easily disconnect the same way. If you connected another way (via explorer), do a net use from command line it should display the current connection if there are still some connection to the computer where you enabled share1, you won't be able to reconnect with another user. You'd need to net use * /d to remove all connected resource and the should be able to connect again to share1 with another user.