What do I need to prepare for a 30-day extension of a 60-day tourist visa at Chaengwattana?

To extend a 60-day tourist visa by 30 days at Chaengwattana, you need to bring your passport, the TM.6 departure card, one passport-sized photo, and 1,900 baht for the extension fee. It's also advisable to make necessary copies of documents, which can be done on-site. The office operates from 8:30 to 16:30, but closes for lunch from 12:00 to 13:00 and stops issuing queue numbers at 15:30.