When you say ‘Elvis Has Left the Building’ you mean that the show is over and it’s time to go home.
Example of use: “Get you coat; Elvis has left the building!”
The phrase ‘Elvis has left the building’ originated in 1956, when Horace Logan, announcer at the Louisiana Hayride Show, used the expression to encourage a crowd of teens to stay seated for the next performance. Later, it was used to encourage Elvis concertgoers to leave the venue.