You just open the custom field and change the current Label to Employee Maintenance (or whatever you would like) and then save. What I am not sure of is what it does to previous tickets titled "New Employee".
Suggestion here is add an additional option " "New Employee" option.within the custom field, and keep the old one. Now search for all tickets with the old custom field entry and bulk change them to the new one. Then delete the
This will ensure that all old custom field matches in old tickets you have with the old name, and will help when you produce queries or reports.
If you've already renamed without changing the old tickets, simply add the old option in again, then search and bulk edit those as described above.
Thank you, I'll give those a try.