Just completed the cancellation of my work permit and extension of stay in Ayuthaya. Not sure if this is applicable to all labour departments, but the process was surprisingly easy. Walked in, told the person at the counter I came for a cancellation and got helped straight away while around 30 mostly Myanmar workers were still waiting with a ticket. Needed to hand in my permit and passport for a copy, and gave them the cancellation form I prefilled in myself (you can also fill it in with the officer on the spot.) The officer DID NOT ask for any documents from the company whatsoever. They even refused company registration certificates, letter of termination and a copy of the directors ID card. It's getting processed as we speak and can pick up the confirmation slip after the lunchbreak. If this process applies to all labour departments it means everyone should be able to cancel their permit without ANY document or signature required by the employer within minutes.