You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: I want to change my existing reservation, can you please help me with that?

ASSISTANT: Sure, May I know your name?

USER: Robert Perez here.

ASSISTANT: We found a reservation with your name, please provide me your airport codes?

USER: My airport codes are PHL and CLT.

ASSISTANT: Can you please share me your travelling dates?

USER: I would like to travel on Apr 14 and return on Apr 16.

ASSISTANT: Do you have any class preference?

USER: No, I am comfortable with any of the class.

ASSISTANT: Do you have any connection limit?

USER: I need connecting flight.

ASSISTANT: May I know your name?

USER: I already mentioned above.

ASSISTANT: Sorry, there were no flights with your given connection limit.

USER: No problem, thank you for the information.

ASSISTANT: Thank you for reaching us.