You can change your password in two different ways, but you need to have your phone number and or email address confirmed in your account: 

1. Log in to your account, go to "My account" and select "Change password". Enter all the required details and save your new password by clicking on "Change password".
2. If you are not logged in to your account, you can use the "Forgot Password" function. Click on "Log in" and follow the steps.