I don’t think this is possible. If you enter under a visa exempt entry (I assume you mean this rather than tourist visa) then your Non-O would be cancelled. That’s my understanding, but perhaps others can comment.
thank you for your advice - that lines up with my own understanding 👍🏻
I previously applied in Bangkok, but this time around will be applying in Phuket due to change of residence. I assume this won’t be an issue?
Also, I know it normally takes around 3 weeks for the extension to be processed - is there anyway that this can be expedited, as I will be out of Thailand again from 17 June for about 8 weeks.