You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Debra Martinez here.

ASSISTANT: How can I assist you?

USER: Do you have any flight from IAD to IAH?

ASSISTANT: Debra, if you provide me your desired dates of journey, then we will let you know about the flights availability, so please provide me the travel dates.

USER: My trip dates are 05/27 and 05/29.

ASSISTANT: Ok, please wait for a while.

USER: Sure.

ASSISTANT: Debra, sorry to inform you that there are no flights available for you on those dates.

USER: That's fine, thanks for your information.

ASSISTANT: Thank you for choosing us.