Thank you very much for your email.
The problem is that I cannot find any flights from China to Siem Reap, even when I searched for other dates. I definitely saw flights before because Siem Reap is a very popular destination. Please let me know if you have any better suggestions.
If this option works (transportation is not a problem), how about travelling from 22 June to 22 July? If you suggest another date, I am also available in August.