Well it seems lots of people do not understand the question. She want to go to a border stamp out Thailand, stamp in/out neighbor country and back into Thailand for a new 30 day Visa Exempt Entry. So she do not need papers for a Non Immigrant B visa from her school, it does not matter which Visa she has in passport and it even does not matter that she used to be a teacher back in S/A.
@Maggie *********
You can do the same border run as you did before, unless that was your second border run this calendar year. As S/A you can only make two border runs a calendar year.