You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Rebecca Roberts.

ASSISTANT: How can I help you?

USER: I am planning to go for my friend's marriage, could you help me to find a flight?

ASSISTANT: That's great to hear.Will you provide your source and destination airport codes?

USER: My city codes are ATL and DCA.

ASSISTANT: Will you provide your travelling dates?

USER: My travelling dates are 03/09 and 03/11. 500 and 1 are my price and connections limits.

ASSISTANT: Please give me a moment.

USER: Sure.

ASSISTANT: Sorry to say that Rebecca, there is no flights available for your requirements.

USER: Oh! that's fine.

ASSISTANT: Thanks for reaching us.Have a nice day.

USER: Thank you for your help.