What departure date should I put on the Cambodia e-arrival card if my flight is before I plan to leave?

Hi all... I'm going to Cambodia this weekend to submit the DTV application. And I'm trying to complete the Cambodia e-arrival card. However, I have a question. It asks for departure date from Cambodia. I have a flight scheduled on May 7. But I know that's too soon as I won't receive an answer yet on my application. And it will cost me more to change the flight than take a bus. So I decided to skip the return flight and take a bus about a week later (although I don't know the exact date since it depends when I get the DTV). So I'm just wondering if in departure date I'm supposed to put my scheduled flight date because that's what it shows with the airline, even tho I may leave a week later? Or should I put the date of a week later?