To erase all user data currently stored on your band and return the band to its original factory settings, then use a Hard Reset. Performing a Hard Reset may also help fix any band performance issues that a Soft Reset is not able to fix.
Make sure your band is charged
Press the button on your band 10 times
On the 10th press, hold the button for 10 seconds until the red LED comes on
Activate and sync your band like you did upon first use