You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I help?

USER: I want to attend an event at Houston, can you please help me to book my flight ticket from PHL to IAH?

ASSISTANT: Let me know your travelling dates.

USER: I would like to depart on Oct 17 and return back on Oct 19.

ASSISTANT: Do you have any preference?

USER: I prefer for an economy class.

ASSISTANT: Can   I   know   your   name?

USER: My name is Deborah Perez.

ASSISTANT: Sorry, no flights found for your travelling dates. Thank you.

USER: Not an issue. Anyway, thank you for checking.