You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello,. How may I assist you?

USER: I am Larry Gonzalez want to travel to Seattle, WA-SEA to meet my son on his birthday. Can you help me in booking a ticket?

ASSISTANT: Sure. Please let me know your travel dates?

USER: My travel dates are 05/28 and 05/30.

ASSISTANT: May I know your boarding airport code?

USER: I will depart from TX-IAH.

ASSISTANT: Ok. I'm sorry, no flight is available.

USER: Ok, thank you for your help.

ASSISTANT: Thanks. Have a nice day!.