extending Thai passport

Sorry for this question because I know it has been discussed before, but can't find it...

Where can a Thai extend `his/her passport or get a new one ? I have never been in a government building in Udon (apart from the police station to pay a 500 baht parking fine) so I have no idea where the offices are.

Thanks for your help.

The link you need Peter .
first-thai-passport-what-documents-needed-t20257.html?hilit=thai%20passport

city hall, wattananuwong road, near Nong Prajak

Thanks a lot gentlemen