To share access with another person, the screen tool can be used.
Log in to the machine where you want to share a console
user1$ screen -S SessionName
SessionName can be any easy string.
Ctrl-a :multiuser on
Ctrl-a :acladd otherLoginAccount
As the second user, access the screen session
user2$ screen -x username/session
At this point, both user1 and user2 have full control of the session, allowing either of them to steer the session.
user2 can leave the session with
user1 can close the session by typing exit at the shell prompt.