Click on the "Team" menu at the top of your Chat Window and it will give you the option to quit the TF.
[Edit:] If you prefer typing to clicking you can simply type "/leaveteam" (not including the quotes, of course).
Kosmos
Global: @Calorie
MA Arcs in 4-star purgatory: Four in a Row (#2198) - Hostile Takeover (#69714) - Red Harvest (#268305)
I'm new to the MA thing. I activated a mission I'm not enjoying. Is there a way to drop it so I can try a different one?