Anonymous participant And you have to make the report as you are 90 days inside Thailand.
That Immigration allows you to make that report between 15 days before and 7 days late if you walk into the office, or 15 days before if done by mail, or between 15 days before and due date if you do on-line, has nothing to with the fact that you are actually 90 days inside Thailand.
You report that you are 90 days inside Thailand, the moment you leave Thailand the count of being in Thailand stops. It starts on the day you enter Thailand as day number 1.
Be aware that if your make a report and get that approved, the next 90 day report date will be 90 days later than the approval date, see the date mentioned on the report, if you stay inside Thailand.
And in your first comment, you tell you can change the reason for an issued Extension of Stay.
As things may sound otherwise to you, I like to give correct information and not I type something that sound easy but is actually wrong.
You forgot in your comment the income requirements.
Again you can NOT change the reason, if you cancel the extension of stay it is cancelled and not valid, you apply for a NEW Extension of Stay with a NEW reason. NEW and NEW is not change what you had.
You can NOT change the reason of your stay after it is issued.
NO, you do not have to resign or get fired to be inside Thailand based on visiting Thai family.
Go to your local Immigration Office, get the hand out of requirements, be aware that there are multiple options to meet the financial requirement, discus this with the officer and see which option does fits you. One of them is income made in Thailand.
Than make an appointment, so you have time to get all needed documents to apply for this 1 year Extension of Stay based on visiting Thai Family.
You can do this before your current stay ends or cancel your current stay and apply for a new 1 year of stay.
I guess you have a big stamp in your passport from Immigration with the text:
"permitted up to xx Nov 2025"
This stay is permitted based on being employed, if you stop working, you have to cancel this permission to stay as signed at application of this Extension of Stay.
If you have permission from Immigration to make short trips abroad while living on a tourist visa and coming back each and every time to the same address, it is no problem.
If you did not discuss this with your local office, I can not tell you.
Officially you have to report within 24 hours after arrival at the address.
That means when you left Thailand and return or when you decide to stay overnight at another address.
Just for extra info. As you mention that you are allowed to be inside Thailand to study, it may be a problem that you leave twice a month to other countries in stead of sitting in the classroom. Be prepared to answer some questions about the need to travel around.