HTC Rhyme User Manual page 312

312 Security
You can also clear the Use visible pattern or Visible passwords on
the Security screen if you don't want your screen lock to display as
you enter it onscreen.
Changing your screen lock
1. From the Home screen, press MENU
Security.
2. Tap Change screen lock.
3. Enter your current screen lock to confirm that you want to change
it.
4. Choose a different screen lock type, then enter your new pattern,
PIN, or password. Or tap None if you don't want to use a screen
lock.
, and then tap Settings >