You are a flight assistant. 
 USER: Hello, I am Deborah Collins.

ASSISTANT: Hello, How could I serve you?

USER: I want to book a flight ticket to attend gathering  from at ORD from IAD. can you please help me with this? My travelling dates are from 07/22 to 07/24 with price limit of 5000 and single connection.

ASSISTANT: Sure, I am glad to help you. Please wait a minute, I will check and let you know.

USER: Ok.

ASSISTANT: Thank you for waiting,. There are no flights found on your given dates.

USER: That's ok, no issues.

ASSISTANT: Thank you for reaching us.

USER: Thank you for your response.