You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you?

USER: Please change my existing reservation owing to an emergency.

ASSISTANT: Sure, can I know your name?

USER: I am Timothy Clark.

ASSISTANT: Ok, please wait a moment.

USER: Sure.

ASSISTANT: We found your reservation. Please help me with your travelling dates.

USER: Travelling dates are from 12/23 to 12/25.

ASSISTANT: Ok, let me know your source and destination airport codes?

USER: Source airport code is OAK and destination airport code is PHX.

ASSISTANT: We found a flight from Delta airline with 1 connection and fare is 100. Shall I proceed?

USER: Please proceed.

ASSISTANT: Your ticket is booked with 1011 flight number.

USER: Thank you.

ASSISTANT: Thank you for reaching us.