In a commercial package policy, an interline endorsement is one that:

Explanation

Interline endorsements are the endorsements that cut across the package rather than belonging to a single line, so one attachment can amend the property, liability and crime parts at once. A nuclear energy liability exclusion is the classic example. An endorsement that touches only the property part is a coverage-part endorsement, and adding an additional insured amends one part rather than crossing lines.