An Admin must access their own account first.
Then, click on Admin on the left side menu of their profile.
After that, click on User that will appear on the top of the left side menu after Admin is selected.
The Admin will then locate and select the name of the user in the list.
Once the user's profile appears, the Admin can select Activate, and the activation email will be resent to the user's inbox.
It will expire within 48 hours.