You can move a user into a different profile by following these steps:
Log in to Dimensions
Navigate to System and then Profiles
Use the green arrows to find the profile that the user will be moved TO
Click Users
Find the required user in the list on the left hand side (users not in this profile) and find the relevant user
Double click on the user name to move them into the right hand list (users in this profile)
Close down all open screens.
The user will need to log out and back in to pick up the changes
The user will now have the same access as others in that security profile.