A urgent question. I just resigned from my company and my understanding is my HR will need to cancel my work permit and also I need to go in person to immigration to cancel my extension of stay then they will give me a stamp to leave in 7 days, is this correct? Because my HR also told me that I don't need to go immigration because when they cancel work permit, the visa/extension of stay is also automatically cancelled?
TLDR : Answer Summary
After resigning from your job in Thailand, you must go to the immigration office to cancel your extension of stay, even though your HR may believe that this is done automatically when they cancel your work permit. You need to bring a letter from your company stating your last day of work, along with the cancelled work permit. Failing to do this may result in fines and the inability to apply for future extensions.