I read the post of Tod about the requirements of Extension of Stay and went to look at those 3 documents.

Thanks for putting them in the files section, but I found this part really important for all our members.

So many times I read that people with an Extension of Stay want to leave Thailand for an other Visa because they changed jobs, school or want to have another Visa.

Be aware that this Extension of Stay must be terminated on the day things change, you signed this document, maybe even without reading it or quickly looking at it, in front of the officer.

This is the English part of that document: