How do I apply for a retirement visa in Thailand while on a limited entry pass?

You need to go to the local immigration office that serves the address on your TM30. Then get that office-specific and latest handout for the requirements for an initial in-country visa application.

As stated, some provinces require you to have a minimum of 15 calendar days, but some provinces such as Chiang Mai require you to have 15 working days or more. Check your current stamp, what type of entry and the date you are permitted to stay.

Here is general information from Immigration Bureau HQ which could give you a rough idea of what you may need, but you need to get one from your province.

/9.FOR-RETIREMENT-PURPOSES-50-YEARS-OLD-NON-O.pdf

You may be out of time already depending on where you are. Most offices require you have 15 days left to apply but some are 21

Go immediately to your local Thai Immigration office and ask for their list of requirements for the Non O Visa as retiree and the One year extension of stay as retired.

What is the Entry pass you refer to when you ARRIVED into Thailand?

VISA EXEMPT?

With a Thai Visa?

Or ???

What's the Date you arrived into Thailand?

Have you extended it at Thai Immigration office, if eligible for a 30 day extension of stay?

What is your passport nation ?