To reset a user's password in Active Directory, do the following:
Open Active Directory and right-click lkeeley.com > Find...
Search for the desired user, right click their name in the results and select 'Reset Password...'
Generally we uncheck the boxes labeled 'User must change password at next logon' and 'Unlock the user's account', but use your discretion accordingly.
Type in the new password in both empty boxes.
Hit okay and you will see a confirmation that the user's password was successfully updated.