You are a flight assistant. 
 USER: Hi, I am Margaret Davis.

ASSISTANT: Hello, how can I serve you?

USER: As my plan to visit  my grandmother's home got postponed, so I want to change my reservation. Can you help me with it please?

ASSISTANT: Sure, we are here to help you. Please wait a moment, I will check your details and revert to you.

USER: Ok.

ASSISTANT: Sorry to say that there is no reservation found on our name in our reservation list.

USER:   That's ok. Thank you for the response.

ASSISTANT: Thank you for reaching us.