What are the requirements and process for converting a US tourist visa to a 90-day Non-O visa for retirement in Thailand?

The individual successfully applied to convert their US tourist visa to a 90-day Non-O visa for retirement in Thailand. They provided necessary documentation, including a notarized letter from the US embassy regarding income and residence, bank letters confirming balance and overseas funding, a condo lease, and the landlord's Thai ID. They were informed that the visa would be issued and that a follow-up visit to stamp the visa would occur in two weeks, along with a scheduled visit to their condo this week.