No. You’ll have to have player 2 in order for the fleet and mission to be open. If you log out player two, the mission cannot be ran without him.
The owner of the mission has to be present.
Unless you are talking about having player two and A warping to area, then logging out two and logging in one.
Then having one and A in fleet and warping and running mission (and if there is a mission item), have A direct trade it to two when you log him back in to turn in mission.
That sounds plausible but such a headache.
Why not just go to discord.unitedstandings.org and have someone raise the standings for B?
Where did B come from?
Having 1 and A together or 2 and A together makes sense. But pulling with 2 and running with 1 and A then contract or trade back to 2 or B just sounds like a heads headache