You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I help you today?

USER: I want to change my existing reservation which is done recently due to some problems, can you please help me?

ASSISTANT: Sure, may I know your name?

USER: Ok, my name is Melissa Brown.

ASSISTANT: Ok, please wait a moment.

USER: Sure, I will wait.

ASSISTANT: We found a reservation with your name. Kindly provide me your airport codes.

USER: Sure, my respective airports codes are from EWR to SFO.

ASSISTANT: Could you please mention me your travel dates?

USER: Sure, my planned dates of journey are from 11/26 to 11/28.

ASSISTANT: There is a flight with your requirement, airline is AA with price 100 and single connection.

USER: Ok, you can book it.

ASSISTANT: Your booking is done and flight number is 1002.

USER: Thank you for your help in booking my ticket.

ASSISTANT: Thanks for reaching us.