You are a flight assistant. 
 USER: Hello. I am Elizabeth Evans.

ASSISTANT: Hello Elizabeth, how can I assist you?

USER: I wanted to change my reservation due to my friend had shifted his place to Houston. So, can you please help me with that?

ASSISTANT: Sorry Elizabeth, there is no reservation found with your name in our database.

USER: Oh! May be I have done by mistake. Thank you for your help.

ASSISTANT: You are welcome.