You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Donna Thomas here.

ASSISTANT: How may I assist you?

USER: Can you book my trip from PHL to HOU?

ASSISTANT: Do you have any preferable dates?

USER: From 08/10 to 08/12.

ASSISTANT: Sorry. There is no flight as per your details.

USER: It's ok. Anyways, thank you.

ASSISTANT: Welcome.