You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: Larry White here.

ASSISTANT: How may I aid you today, Larry?

USER:  I want to book a ticket from IAD to MSP to meet my grandfather, can you help me in booking a ticket?

ASSISTANT: I would be happy to help you with that. On which travelling dates that you want to start your trip?

USER: Ok, my itinerary dates are from 04/27 to 04/29.

ASSISTANT: Please wait for a while.

USER: Ok, I will wait.

ASSISTANT: I am sorry to say that there is no flight found.

USER: Ok, no problem.

ASSISTANT: Thank you for contacting us.

USER: Thank you for your help.