You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I assist you?

USER: Thomas Miller here. I want to book a ticket from HOU to SFO, can you help me?

ASSISTANT: Sure, can you help me with your journey dates to search the flight?

USER: My dates of journey are from 10/20 to 10/22.

ASSISTANT: Please wait for a moment.

USER: Sure, carry on.

ASSISTANT: Sorry, there is no flight is available for you.

USER: No problem, thank you.

ASSISTANT: Thank you for choosing us, have a nice day.