1) Decouple 2) Detach 3) Undo 1) Decouple 2) Disconnect 3) Disconnect or separate 4) Loose a caboose 5) Separate 6) To come loose 
• (v. i.) To roam at liberty. • (v. t.) To loose, as dogs, from their couples; also, to set loose; to disconnect; to disjoin; as, to uncouple railroad cars.
[v] - disconnect or separate