Conditions

Voluntary

When a customer requests a change of airline or re-routing (as described in IATA Resolution 736), the Star Alliance member carriers agree to grant airport control (thus waive the endorsement requirement between themselves) for non-restricted tickets or MCOs provided that:
A. such tickets or MCOs do not bear carrier validation restrictions, which by their terms prohibit the transfer of the ticket or MCOs such as "Valid on XX only" and "Non-Endorsable";
B. such tickets or MCOs are not governed by fare rules that prohibit transfer of the ticket to the other party.
No endorsement required for First Class, Business Class, full Economy Class and non-restricted excursion fare tickets.
Does not apply to ID/AD tickets.

Involuntary

When an airline undergoes a schedule change or encounters an irregularity in accordance with the general provisions of IATA Resolution 735D, the Star Alliance member carriers agree to grant airport control (and thereby waive the endorsement requirement) for the following:
A. non-restricted tickets;
B. restricted tickets;
C. frequent flyer redemption tickets.
No endorsement required for any fare types when an airline encounters an irregular operation (within 24 hours of departure).
Does not apply to ID tickets.