Also, what about my WP. Will immigration ask for proof that its been cancelled or can it ride?

Thanks Tod. The 400k is in my Thai account now. How do I show that it came from outside Thailand? I assume visa exempt is what I incorrectly refer to as a tourist visa?

Robert/Scott. Thank you for your knowledge. i am definitelyt not questioning your advice but it's amazing the different advice you get. I have a friend of a friend who is an agent. She called her 'friendly' IO, who said " He can cancel Non B then cross and come back (bounce) the same day and apply for Non O marriage. He only needs to have 400k but not necessary to have been in for 2 months (as it's not an extension), no need to cancel WP." I double checked as I was previously advised to get extension based on visiting family whilst waiting for 2 months maturity of money, (I have 2 kids with Thai wife). I too thought I'd have to cancel WP but she says I am not quitting the job but as you say technically I am. I guess I'll have to reapply.

Thank you, I have forwarded your advice.

Sorry about my poor wording.Yes, he has an extension of stay based on retirement (over 50) as per your second post and wants to extend based on marriage. He would find it difficult to have the 400k but can show 40/month. My question is - can he show the 40/month? The reason I ask this is, if I understand correctly, on applying for the original visa one has to have 400k in a Thai bank, but an extension one can show either?