Correcting mangled asset numbers

In our FA configuration the Asset Number is set equal to the Asset ID when the asset record is added; the Tag Number is the primary equipment identifier.  For several assets users have been able to change the Asset Number (which should be all numerics) to alphameric data that is invalid.  But --- they cannot change the incorrect Asset Number value to their numeric (correct) value because of a form protection function.  The error message states that "This field is protected because it is a numerical sequence."  I have asked the users to reset the incorrect Asseet Number values to