What are the requirements and tips for applying for a marriage extension in Thailand?

A few notes from my ALMOST 100% successful application for my third marriage extension at CW today.

One copy of supporting documents only was required the IO returned the second copy.

Bank book update was done by the machine outside Bangkok Bank in the basement after transferring 50 baht in today to ensure balance was shown. Letter and statement were obtained at my local branch yesterday and were accepted.

I submitted STM 2 and STM 9 acknowledgment forms with my application but IO provided 2 additional forms STM 10 and 11 for completion at the office which were authorization for fact checking and affidavit of relationship.

Visit was almost 100% successful because my wife forgot ( and I didn’t check) to put original marriage certificates in the bag and as a result she has to go back tomorrow to show them to the IO.

Under Consideration stamp was put in my passport with a return date of 6th August and a pencil note “ Additional documents awaited” in Thai added

Note that we gave an updated KR2 issued last Friday to the IO but she said that she wouldn’t accept it in lieu of the original documents as it was issued too long ago. IO also offered to give a 6 month extension only if we didn’t want to return with the original certificates! I said no thanks my wife will bring the original certificates tomorrow.

IO complimented us on excellent document preparation but said don’t forget your original marriage certificate next year!

Note this was my first extension in my new passport and they didn’t ask to see my old passport.

90 days report was checked and copied.