You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you today?

USER: Donald Baker here. Can you please assist me in booking a flight from EWR to SFO?

ASSISTANT: Yes, I will definitely try my best to help you in booking your flight ticket. Could you please provide your planned dates of journey?

USER: Thank you, I will leave on Apr 17th and will return back om Apr 19th.

ASSISTANT:  Do you have any class preference?

USER: No, I am comfortable in any class.

ASSISTANT: Do you have any other specifications on your trip?

USER: I am looking for a direct flight which returns back in the evening time.

ASSISTANT: Ok, please wait a moment.

USER: Sure.

ASSISTANT: Sorry to say, no flights found with your requirement.

USER: Oh, I need to look for an alternative to travel.

ASSISTANT: Thanks for reaching us.

USER: Thank you for your time.