Need to relocate vent pipe because taking out existing wall

[KennySackman]

Would the drawn out scenario be ok? I'm taking out a wall to make out bathroom larger and accommodate a tub and shower instead of just a small showe kit. I would need to relocated the vent pipe as it runs up the wall I want to take out. I will be installing a new wall about 2 feet back from it and want to run the drain pipe up that wall and then connect to existing vent out the ceiling horizontally in the attic. I have attached a rough drawing of what I want to do since this seems like the easiest thing for me to do.

 

[KennySackman]

I want to connect to existing vent pipe out of the roof horizontally in the attic so I don't have to move the vent and put a new hole in the roof.

 

[Sponsor]

 

[KennySackman]

Or could I do the top scenario and connect to the pipe that goes out the roof in the attic horizontally? So I would cut the pipe in the attic and put a 90 turn in it and run it horizontally in attic to location of new pipe running up new wall.