My experience sending in a DONE4 for reissuing with SYD CTO:
1) Set up the new itinerary with the ATW desk
Originally had MNL-xHKG-DPS-xHKG-MEL-CNS-MEL-xLHR-MCT-xLHR-IST-LHR-LAX-SJU-ORD-AUS-SEA-DFW-JFK-NRT-MNL. Flown the first 4 (MNL-xHKG-DPS-xHKG-MEL), AA shrunk its network in the US and because my US segments were open I was left unprotected. Yes yes, a case of do what i say not what i do.
But the aagent I spoke to at ATW inserted a remark in the PNR "NO CHRG FOR REISSUE DUE SKED CHG", I'd assume this would be ignored when the PNR gets sent to tariffs though. Not that I'm complaining otherwise.
Had the new itin booked: MEL-CNS-MEL-AKL-xSYD-xLHR-MCT-xLHR-IST-LHR-LAX-AUS-xORD-SEA-JFK-xNRT-MNL, with dummy dates for the bits after LAX. Unfortunately as the original tkt was handwritten there was no record of it in the system - PNR cannot be queued to Dublin for reissue mask as they cannot "see" what i have flown.
2) Called BNE call centre, told the chick what I wanted, got the address of SYD CTO - record of convo placed in PNR.
3) Sent my ticket to SYD CTO last Weds via regoed mail, with an explanatory note so they don't go 'wtf?!' when a random paper ticket turns up.
4) Today I got a call from SYD CTO saying that they've got my ticket, with an exclaimation of how retro it was. As I've only got 16 segments left the aagent expressed her confidence that it'd be reissued as an electronic ticket. And that it should all be sorted out by tomorrow.