I started Into Darkness, but paused the mission halfway through to increase my skill lines before going back. Now I can't figure out how to restart the mission?
Since it was a mission started via a cell phone call, there isn't really a "go back to where you received the mission" option (that I'm aware of).
I tried going back to the New York park where you need to find the agent, but that didn't trigger it.
Best Answer
You can go to you Faction HQ to retrieve it. Where exactly depends of your Faction. According to this forum thread:
Dragon : On the pond outside the Dojun, next to the "Special Assignment" (Venetian Missile Crisis). (Confirmed by a friend)
Templars : In Sonnac's room, on a desk behind him, next to the same mission. (Confirmed personally)
Illuminati : In Kristen Geary's Room, on the desk, next to the same mission. (Not confirmed personally)
I have no proof, but it seems logical that the other faction missions (London Undergroud, To Catch A Thief, Rogue Agent) can be retrived at the same spot.