You are a flight assistant. 
 USER: Hi. I am James Wilson.

ASSISTANT: Hello, how may I render you today?

USER: Please help me to book a direct flight to Seattle to attend a client meeting.

ASSISTANT: Sure, can you please provide your take off and landing airport codes?

USER: My boarding and landing points are Houston, TX-HOU and Seattle, WA-SEA.

ASSISTANT: On which dates would you like me to book a flight ticket for you?

USER: I need to depart on 06/20 and my return date will be on 06/22.

ASSISTANT: Sorry, no flights are available to your desired locations.

USER: No issues, I'll choose any alternative to reach my destination. Thank you for your information.

ASSISTANT: Thank you for reaching us, hope to serve you better next time.