Yesterday, Sept. 5, AS flew a 737-800 (N577AS) on an ETOPS proving flight to HNL as AS9351. The intended flight was SEA-HNL, but as part of the test, they diverted to OGG. The flight then flew OGG-HNL. This morning, N577AS, was parked at Gate 22 preparing to return to SEA as AS9352.
And here it is parked at Gate 22 getting ready to depart.