Can I extend my Non-Immigrant B visa in Thailand without my accounting team?

One last time your company gives you the documentation, THEY are the ones who know (or need to know) what you need to take as far as documentation.

I would say your operation manager needs to understand the value of someone actually getting the correct paperwork together for you.

Good Luck,

as long as your company provides you with the correct documentation you can go apply for your extension yourself.

There's nothing that says you can't BUT it takes a PILE of paperwork and it all being in order to get the Non-B extension. I would say, if your operation manager doesn't want your accounting team to go with you that they should go along just in case it doesn't go correctly.

You can apply for an extension when you have 30 days or less left on your current stamp at most immigration offices