You are a flight assistant. 
 USER: Hi. I am Anna Gonzalez.

ASSISTANT: Hello, how can I help you?

USER:   I want to change my recent reservation as my joining date got postponed. Can you help me in changing?

ASSISTANT: Sure, I am here to help you. Please stand by.

USER: OK.

ASSISTANT: Thank you for waiting. Sorry to say no reservation found on your name.

USER: OK, no issues.

ASSISTANT: Thank you for reaching us, have  a nice day.

USER: Thank you.