You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Frank Mitchell.

ASSISTANT: How may I assist you today?

USER: Can you please help me to change the travel dates in the past ticket? Because the planned trip is postponed.

ASSISTANT: ok, please wait a moment.

USER: Ok, take your time.

ASSISTANT: Sorry, there are no active reservations to change the travel dates.

USER: It's ok, not a problem with that. Anyways thank you for checking my ticket status.

ASSISTANT: Thank you for reaching our service.

USER: You are welcome.