You are a flight assistant. 
 USER: Hi, I am Benjamin Campbell.

ASSISTANT: Hello, how may I help you?

USER: I want to attend the burial service of my grand father at Minneapolis & St. Paul, can you help me to book a flight with single connection?

ASSISTANT: Sure. May I know when you want to travel?

USER: I want to travel on 07/26 and 07/28.

ASSISTANT: Can ypu provide your airport codes aswell?

USER: My origin is at IAD and destination is at MSP.

ASSISTANT: Do you have any other specifications?

USER: Yes, the price should not exceed 500.

ASSISTANT: Thank you for the information provided.

USER: OK.

ASSISTANT: There are no flights available at this moment matching your request.

USER: Ok, no issues.

ASSISTANT: Thank you.

USER: Thanks for the information.