This SQL will give you all the records that are currently in your table for this [employee no] that also have the transferedtolocation:
Code:
SELECT [employee no], [transferedtolocation]
FROM IHaveATable
WHERE [employee no] = 123 and [transferedtolocation] = 456;
The "123" would be whatever the employee no is that you are currently working with, and "456" would be the transferred to location that you are interested in for this transaction.
The form you are dealing with will have an event named BeforeUpdate that you can use to enter the VBA code to run the query with the SQL I have suggested. If the query returns any records you will know this employee has been transferred to this location before.