Originally Posted by nmpls

IDK, maybe I'll give a data point for people. I have just booked two tickets SFO-TYO-SFO, one for me and one for my wife, for late 2025. She needed to return earlier than I did, so her booking leaves a week before mine.
We were pretty inflexible about the departure date, but had more flexibility on the return other than having a hard stop for each. I allowed myself a 3-4 day range on the return. Due to my inflexibility, I decided to just do PE on the outbound, as getting 1, much less two outbound SFO-TYOs in J seems impossible. Normally, I'd have thought that I could wait until the day the return ticket was ready to book, but looking at Saturday departures in the proceeding weeks showed that even PE was a hot commodity on Saturdays. As they only release 1 ticket per flight in PE, at least on weekends, we have to fly different flights but there are 2x SFO flights which is nice. I'm leaving earlier, which is a rough time to fly PE as I'd prefer to sleep. But happy life, happy wife prevails. Then return in J.
In any event, the plan was to book Saturday with return on the next day (sunday) when the first business class came available, I was unable to book both 355 from Sunday, but I booked one for Saturday-Sunday and the other Saturday-Monday. The plan was then to change each ticket every few days to avoid the 10 day time out issue. This worked great until 10 days from booking. I didn't get the normal message people get on an ungardened date change. Instead, it showed business class available and then when you clicked through is showed a downgrade to PE with a refund of 16.5k points. Thankfully I caught this.
I called ANA and they could not unglitch this. They could change our dates from one to the other in J, but the online change was permanently broken. I don't know if this is some one off glitch, but I'd be curious if anyone else has gotten it on mixed award reservations.
As a result, I had to call. And honestly this was less of a nightmare than I thought. I called in 4 days in advance of the goal date and moved it up, with the idea that I could accommodate missing a day or two without it being a disaster. At the end, I got my goal return dates for both flights. In earlier posts, people talk about calling in hours early. This seems unnecessary at least in November and December. I made a practice of calling in at 8:35am Japan time every day. This connected me somewhere between 12-5 minutes before 9am every time except 3. Each time I called in then the very helpful agent put me on hold for the time needed.
The two exceptions were.
Japanese Wednesday. Both times when I called in on to change from a sunday to monday flight (Tuesday in the US, Wednesday in Japan), I got connected almost immediately. It was too early to hold. I called back at 8:45 each time and connected with plenty of time. I guess Mondays are the least popular day to fly? The final exception was the day after the first Wednesday call, I called at 8:44 the next day and connected at 9:05 and all tickets were gone. This was my only miss.

The ANA staff were awesome, a real breath of fresh air from most customer service. They're polite, patient, and generally understand exactly what I wanted. While they managed expectations by saying the would try to get the change with no promises, in every case they got not just a flight, but my preferred flight (Nh8 v. NH108) as long as I connected before 9am.

I am not 100% sure I'd put myself through this again. Having to call at 3:30PM (pacific) every day was pretty annoying and I was lucky to be able to avoid having things scheduled for these days. Its much worse than just having to click a button and fill out some forms at 4pm. I feel like this is probably a quirk from mixed booking, so people may want to avoid that if they cannot call in.
The other option is to not book your flight until 10 days before your desired return. That didn't seem like an option as we had to fly out on one date. It seems to have paid off because even Y is waitlisted for some flights that day.
One thing I would note for SFO-TYO, is that when I do search for availability F seats seem to go much, much slower than J. Like right now on my return date, J was listed as waitlisted with 2-3 minutes, but now, 33 minutes later F is still there. If you points allow for that, its worth considering, I kinda wish I had.

Finally, fun thing, fees went down. At my booking in october, my total was ~$450. When I started calling on the second ticket in December, I got a refund of over $100, which means the fees are only about $350 this month best I can tell. I'm sure amex loves all the little $2 refunds and charges from all the other changes.