Can map_server load a new map at runtime after starting?

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I want to have my robot load a new map if it moves off of an existing map into another space. I know how to use the map_server node to load a map when it is started up, but can I then tell it to load a different map without having to stop and re-start the node? What is the best way to do this? I looked at the map_server wiki and I don't see any service for 'set_map' or 'load_map' or anything like that.