Changelevel
The changelevel console command will end the current game, load the specified map and start a new game on it. The main difference with map is that the players are not kicked from the server. This command can only be used in multiplayer games.
Usage

<
and >
characters.Syntax: changelevel <mapname>
(Without .bsp extension)
Can access both maps in mounted GCFs and in the local mod/game maps
folder.