Step 1.) Navigate to Active Directory Users and Computers on a domain controller with access to the user's account that is to be changed.
Step 2.) Locate the user in question for which the UID is to be changed.
Step 3.) Right click on the user and choose "Properties".
Step 4.) Locate the Unix-Enabled tab in the user's properties.
Step 5.) Manually change the UID to a new Unix ID
*NOTE* The new UID needs to be unique and not conflict with any current UID in the environment. There is no automated way to do this currently.
Step 6.) Click "Apply" and "Ok"
The User's Unix ID has now successfully been changed, please wait 5-10 minutes for the changes to replicate before logging in with this user.