You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: My name is Pamela Baker.

ASSISTANT: Yes, Baker.

USER: I would like to change my existing reservation. Can you help me?

ASSISTANT: Sure, please be on hold.

USER: Ok.

ASSISTANT: I found your reservation, please provide me the airport codes.

USER: Sure, the journey airport codes are SFO and OAK respectively.

ASSISTANT: May I know your travel dates?

USER: I would like to travel on dates 01/27 and 01/29.

ASSISTANT: UA airlines is having a flight with travel charge of 100, shall I proceed booking?

USER: Please book the ticket.

ASSISTANT: Your ticket has been booked with flight-1024, have a safe journey.

USER: Thank you for your assistance.

ASSISTANT: Thank you for choosing us.