To edit HL7 data types click the 'View HL7 Data Types' button in the HL7 Segment Elements window. To create a new HL7 data type click the 'New DataType' button. To edit an existing data type select it in the 'Data Type Codes' list and edit the field values directly in the Data Type Components section. After editing an existing component or adding a new one a 'Save Changes' button will appear for you to commit your changes.

The HL7 Data Types window