How to change your password in the back-end:
1. Login with your current login details and click on your name.
2. Change the password, and click 'Save'.
How to change your password when using the App/front-end:
1. Go to the 'Actions'-menu.
2. Click on 'Settings'.
3. Click on 'Your profile'.
4. Click on 'Change Password'.
See also: I forgot my password - what to do?