2009 Honda Civic/Check Engine Light On
 

I have a 2009 Honda Civic LX. I had performance headers installed on my vehicles in June. After a few hundred miles I now notice that the Engine Light is now on. I had the code checked and it's reading a fault due to the catalytic converter no longer being on the vehicle. Is there anyway possible to have to clear the code and turn the light off? I've been the mechanic shop that installed the headers and the reset it with a code flasher but it reappeared a few mins later. Thanks for the help.