On the Tools menu there is an option called Update 035 for updating the system control number. This will insert a new 035 tag made up of the control number from the 001 tag prefixed by a specified control ID.

You might typically use this option, for example, when you are downloading records from an external source. When you upload the record to your database, the original 001 and 003 information will be replaced with new ones. So, if you want to keep this information, e.g. if you want to be able to search for the record using this information, store it in the 035 tag.

Once you have opened a file of MARC records:

1. Click Update 035 on the Tools menu.
2. Update all records is selected by default, but you can click Update selected records if you have selected specific records.
3. Enter the prefix you want to use in the Control ID box.
4. Use for all update records is selected by default, but you can click Use if 003 not present if you only want to use the Control ID if the record does not have a 003 tag.
5. Click OK.