Problem logging into Chat room with correct user name

My user name is acca4me and login name is Getacca. I am trying to log into the chat room with this name using my friend’s computer who also has an OT account. Everytime I try, even though I log in, It is automatically going in in my friend’s name (kphilbrown). I need to get the login screen for the chatroom so I can change the username, but don’t know how to do so. Can u help urgently with this?