You are able to do this yourself as an admin in your domain.
Here's how:
1. Click the All Users shortcut on the left hand side navigation
2. Search for User in the white box under the word users
3. Click on their name
4. Click on their name again in the slide out box (blue text at the top)
5. Click on Personal
6. Click on User Account and Personal Details
7. Scroll down to the bottom of the User Account and Personal Details Page
8. Select ‘Can view domain users’ checkbox
9. Click Save