How a library revises its catalog depends upon the kind of catalog in an online catalog the revision process depends upon the software employed in the catalog if the software provides global update capability the revision of many bibliographic records at once is simple if they must be revised one by one the process is still immensely easier than revising cards in a card on which they appear or on the subject entry card alone if in a card catalog replacement of a term is desirable but the number of bibliographic records to be revised is prohibitive a history note can be used instead a history note is simple a card at both the old and the form indicating the change when for example the heading insurance health is changed in sears to health insurance the two cards would read ad follows