What is the element ID of the User ID field? To find this out you will need to login to Designer as a super analyst, click File | Windows | Views, Highlight the Default view and click 'Open' and then highlight the details window and click Modify. Double click on the User ID element and make a note of the element ID.
If the Element ID is CUSTID, you will need to replace the existing CustID with the employee number in a large number of tables.
To identify the tables you would need to update, run the Change Data utility (Start | Programs | Touchpaper Software | Helpdesk | Utilities) on the server and Highlight the CUSTID Element ID in the list. The list box below will then give you all the table ID's which contain the CUSTID field. You will need to make a note of these tables and then generate an SQL script to update the CUSTID in all the tables listed with the new employee number.
If you are using ServicePortal then I would advise against making these changes on your own and instead would advise you to contact Support for assistance.
Make sure you take a backup before making any changes to the database and restore immediately if you have any issues.