Can I change my reservation?

Meaning

Requesting a modification to an existing booking.

Examples

• John: Hello, I need to speak to someone about my booking.
• Alice: Certainly, sir. What can I help you with?
• John: <b>Can I change my reservation</b>? I need to move it to a later date.
• Alice: Okay, let me check. <b>Can I change my reservation</b> to reflect that?