Altering Co-pot

[JregGT]

Evening folks, only a quick, and relatavely straight forward one. My car runs lovely, but I have had to alter the co-pot to around 350ohms, so i'm thinking this is quite rich? My question is though, is it safe/able to alter the co-pot while the car is running.
I ask this because i'm going to MOT the car agian this month (to shift it from Jan, as its just no fun doing jobs that must be done when dark/cold/wet after work everytime a MOT rolls round.)
But I imagine when I get to the MOT station they are going to say the emmisions are too high, so wondered if I can alter it while it is running on the exhaust gas analyser.

Cheers folks

Rich 

[cheys03]

Yeah no problem at all to adjust when running

[JregGT]

Thanks for the reply matey, hope you and your car are well.