You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: Lisa Gonzalez here.

ASSISTANT: How can I help you?

USER: Please search flights on these routes IAD to OAK?

ASSISTANT: Sure, may I know your travel dates please?

USER: I would like to go on 04/22 and return on 04/24.

ASSISTANT: Please be on hold.

USER: Ok, carry on.

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

USER: No problem, thank you so much.

ASSISTANT: Thank you for choosing us.