This is easy. As a user you can reset the password for your account by clicking on the forgotten password? link at the bottom of the login page.

Account Owners  and Account Admins of a multi-user Company Plan can reset the password of their account's Writer Users via account admin>manage users.

Simply click on the edit icon to the right of the user's name and you'll be directed to the Edit Writer User page for that user. 

Click on the send password reset email button in the bottom right and an email inviting them to reset the password for that account will be automatically sent to the registered email address for that user as displayed in Email Address field.