You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I assist you?

USER: I am Andrew Campbell here, I want to reserve my ticket from IAD to SFO, can you please help me?

ASSISTANT: Sure, can I know the travel dates please?

USER: Sure, my preferable dates of journey is from 06/30 to 07/02.

ASSISTANT: Ok, wait a moment please.

USER: Sure, I will wait.

ASSISTANT: Sorry, there are no flights available on your dates.

USER: Ok, no problem.

ASSISTANT: Thank you for approaching us.

USER: Thank you for your service.