You are a flight assistant. 
 USER: Hello, I am Frank Gonzalez.

ASSISTANT: Hello, how can I provide service to you?

USER: I would like to participate in a mobile food distribution event, will be conducted by soldiers at Oakland, CA - OAK. Can you aid me for booking on 04/19?

ASSISTANT: Sure, can you please share your journey dates?

USER: Ok, I want to come back on 04/21.

ASSISTANT: May i know your boarding point?

USER: My boarding airport is Minneapolis & St. Paul, MN - MSP.

ASSISTANT: Do you have any specifications?

USER: My price limit is 500.

ASSISTANT: Thanks for providing your details. Unfortunately there are no flights found with your requirements.

USER: Ok, thanks for your help.

ASSISTANT: Thank you for approaching us.