Could someone with great wisdom and generosity enlighten me as to how the Thai Pass works? I applied on November 15th and still have not received word despite a planned Dec 2 departure. I am expecting to have to cancel everything and rebook for after December 15 to make sure I don't have to pay $200 to the hotel for naught. The Thai Pass has an expiration date. I read in a Barrow article that itinerary changes can be made as long as it is within 72 hours. Precisely, what is this change? Is it that the rebooking has to be made by 72 hours after being TP approval and I can fly as late as the the day before the Thai Pass expiration or is it the new flight must depart no more than 72 hours after the flight I used to apply for the Thai Pass. I thought it meant the latter but now I read the Thai Pass comes with a  long expiration date that would reason it is actually the former. Thanks for the help.

You need to check Thailand Pass about your approval. Two weeks is more than enough time.

The expiration date really means nothing since the arrival date is what matters.

You can change your arrival time as long as it is within 72 hours of what is shown on the QR code. But you do have to change your hotel reservation. 

Click Genral Info here. https://consular.mfa.go.th/th/content/thailand-pass-faqs-2