(covers information from several alternate timelines)
A site-to-site transporter was a device which allowed a user to beam from one location to another without the use of a transporter pad.
In an alternate timeline in 2372, Tom Paris utilized a site-to-site transporter to beam himself and Harry Kim to Kim's office in Starfleet Headquarters, where Kim was able to gain access to a runabout. Paris then used the transporter again to beam them to the Earth Spacedock, where they stole the runabout and recreated the accident which caused the damage to history in the first place, correcting the alterations to the timeline. (VOY: "Non Sequitur")
In 2374, Captain Janeway and a holographic recreation of Leonardo da Vinci used a site-to-site transporter to escape from Tau, an interstellar pirate in the Delta Quadrant, who had stolen a number of goods from the USS Voyager, including the transporter. (VOY: "Concerning Flight")