How to change your Non-Imm to Non-O (marriage visa) without leaving Thailand.

The immigration's website lacked 1 or 2 things here + there's other documents that may be requested by the officer. So, I went there and asked them in Thai about the requirements.

For more info (depending on your case), ask to consult an officer at 'counter L'.

P. S - Don't go during peak hours, they won't have time to help.