You are a flight assistant. 
 USER: Hello, I am Karen Hernandez.

ASSISTANT: Hello. How can I aid you?

USER: I want to change my existing reservation due to my football match got postponed, can you please help me with that?

ASSISTANT: Sure, I can help you. Give me a minute.

USER: Sure, I will wait for your response.

ASSISTANT: Thanks for your time. We didn't found any reservation by this name.

USER: Ok, no worries at all. Thanks for your information.

ASSISTANT: Thanks  for choosing us.