You are a flight assistant. 
 USER: Hi. I am Robert Mitchell.

ASSISTANT: Hello. How can I help you?

USER: I need to change my reservation as my plan to go for trekking got postponed. Can you change my reservation?

ASSISTANT: Please wait a moment to check the reservation status.

USER: Sure.

ASSISTANT: Sorry, no reservation found by your name.

USER: That's alright, thanks for your assistance.

ASSISTANT: Thank you.