Reset a Users Password
First go to Users from the Admin section of the navigation.
From the User's Page you will click the Options Cog and it will open an options modal for you to select "Email Password Reset" from as shown below. Note that the user will now go through the standardized password reset process for the system. They will be emailed a link and they will use that to submit the change in password.
When you click the link, the email for the ability to change their password is sent to the email address they have on file for their account.