I was wondering if someone could explain to me, in 'blonde' terms, the process and any potentially undesirable consequences of reissuing a DONE4 b4 departure with NRT origin (dealing with AA).

Some burning questions:
- There's no mention of $125 reroute fee in the fare rules for reiss before departure for TC2/3 origin - meaning it's free to reiss/reroute my ticket b4 departure?
- Is the reiss/rerouting b4 dep effectively canceling my existing ticket and getting a new one? If so, do they refund me on the spot for the existing ticket so that I can pay the new fare for the fresh ticket? Or do they just tag on extra taxes and charge that extra amount?

Thanks.

PS - I got myself a modified itinerary just to get an etix so that I can do remote payment and obtain ticket numbers prior to arriving in NRT. Initially I thought I'd stick to etix and not worry about reiss until some point later in the trip. But the AAgent I dealt with was VERY insistent that I'd still get a paper ticket back even if there are only <16 segments left on the ticket when I reiss as they count the TOTAL number of segments including the ones flown (confirmed by a supervisor but it doesn't sound right to me???), which prompted me to think that it might be easier just getting a paper tix from the start w/o $125 penalty.

PSS- Yes I'm well aware that paper tix with AA at NRT with >16 segments means spending at least 90 mins in front of the ticket counter.

PSSS - Why hasn't the 'print itinerary' tab turned into 'print itinerary and receipt' when my etix has already been issued with status "Ticketed - <date>"? AA web services said it's because I didn't book my itin online but I know that's not the reason because I've had plenty of itins booked with AA CTOs and I've always been able to get my receipt on AA.com. NRT emailed me an etix receipt but it didn't have info about validity/endorsements and the like on it.

Sorry for the long and kinda OT OP.