Removing Oxygen Sensor Questions

ok, so trying to take off the passenger side cylinder head.
a lot of the header bolts are stripped, so i planned to do what i did when i took the drivers side cylnder head off; i disconnected the header from the exhaust pipe and took the head and header off as one piece.
so, i think this should be easy enough. i go under andthen i see i cant get to the nut at the exhaust pipe flange because the oxygen sensor (i believe its the oxygen sensor) is right in the way. i assume theres no other way for me to get the exhaust pipe off than to take out the sensor.

so, anything special i need to do or just stick a wrench on it an turn? looks pretty cramped there.
i would have tried it already but i dont have the right size wrench for the sensor nut.
anybody know what size it is?

is there a way to get the exhaust pipe off without removing the sensor? (i dont believe so)

thanks in advance for any help

thanks
going to try and use a swivel on the exhaust pipe connection to header first and see what happens