Data Validation Lists - Allowing no other entries
 

I am using a drop down list for categorization, however, frequently the
category titles change, is there a way to force the data to change when I
update the master list? Currently I have to change each entry in my register
to match the new category title. This isn't too hard as I can use find and
replace, but I would like the entries with the old title to no longer be
valid and be forced to be updated.

Also, can I have the cells auto-fill from the list?
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KKD