Update, already processed the cancellation. Wasn't told I had to leave but then again they didn't say anything except hand the passport back. Unfortunately everything is in Thai and there's no "Cancelled" stamp. Anybody else have been through this process yet and can share what a right cancelation stamp should look like?
I'm not sure about that. All other comments on this forum says it has to be cancelled in the immigration office, not doing so can potentially be fined. Also checked the extension stamp and reentry on the passport, nothing indicates they are cancelled.