How can I switch banks while maintaining my Non-O visa status in Thailand?

Switching banks for non-O visa.

I am currently on a Non-O visa based on age (Bangkok Immigration) and plan to switch banks. I want to ensure the process goes smoothly without disrupting my visa status.

Planned steps:

1. Transfer 400,000 THB from the old bank to the new bank six months into my current extension.

2. Once the first transfer is confirmed, transfer another 400,000 THB.

Documents I plan to prepare for visa renewal:

a. Old Bank:

• Bank letter confirming the account.

• Bank statement showing both transfers (up to the day after the second transfer).

• Updated bank book showing the balance after the second transfer.

b. New Bank:

• Bank letter confirming the account.

• Bank statement starting from the day before the two transfers to show the incoming funds and balance of 800K at least 3 months before the extension date.

• Updated bank book showing the balance as of the visa renewal date.

I guess my question are:

1. Do i need to keep the old bank open until the extension renewal, or showing the overlap of transactions between old and new bank is good enough? (Will not keep old bank)

2. Which banks have a branch in Chaeng Wattana where I can update my Bank book (I heard Kasikorn closed their branch there).

Thank you