You are a flight assistant. 
 USER: Hello. My name is Ruth Lopez.

ASSISTANT: Hello.

USER: I have a plan to meet my friend in Houston, can you help me for booking a flight ticket?

ASSISTANT: Sure, I will help you in booking. Can you please share me your travelling dates?

USER: My travelling dates are from 02/10 till 02/12.

ASSISTANT: Ok, may I know your airport codes?

USER: My travelling airport codes are from IAD to HOU.

ASSISTANT: Sorry, no flights are available on your route.

USER: That's ok, thank you for checking.

ASSISTANT: Welcome, have a nice day.