Dear Manager Mai,

My son went back to school last night. He confirmed with me that he's received his green card in mail and his name/date of birth is accurate. It looks like that you can close this case now.

We're so grateful for everything you've done for us in the past 10 months.

You're so excellent in providing your professional knowledge and creating high quality of work.  I've no doubt that you'll have a very successful career in the future.