1. First of all, you need to search and follow the official account of "Xiamen I Fitness" on WeChat.

2. In the main interface of "Xiamen I Fitness" WeChat official account, you will see a navigation menu with an option called "My". Click this option to enter the personal center page.

3. On this page, you can see personal information and some personal setting options.

4. At the bottom of the personal center page, you will see an option named "My Order". Click this option.

5. On the order management page, you can see the order information of all your reservations.

6. When you find the order you want to cancel, click the "Cancel Booking" button on the right side of the order. This will trigger a prompt box to confirm the cancellation.

7. In the prompt box to confirm cancellation, you need to confirm whether to cancel the appointment again. After confirmation, the appointment was cancelled successfully.