Hi.
user
Hello. How can I assist you?
assistant
I want to change my reservation, can you help me?
user
May I know your name?
assistant
I am John Hall.
user
May I know your new travelling dates?
assistant
My trip dates are 12/20 and 12/22.
user
Can I know your travelling airport codes?
assistant
My airport codes are from OAK to DFW.
user
Do you have any other preference?
assistant
I want to return in the evening.
user
Sorry, no flights available on your route to alter your ticket.
assistant
No problem, thanks for checking.
user
Thank you for reaching us.
assistant