My family memberhas a upcoming round trip international flight.
NRT-SFO-DEN / DEN-SFO-NRT on L fare

My family member found out NRT-SFO / SFO-NRT is available on S fare

The price of NRT-SFO-DEN / DEN-SFO-NRT (L fare) is higher than NRT-SFO / SFO-NRT (S fare) + SFO-DEN / DEN-SFO (L fare).

He wants to change the ticket online. However, he can not change outbound and return at the same time. Only change outbound or return at a time.

It looks like cancelling and rebooking is not an option since there is a cancellation charge on his ticket.

Is there any method to change outbound and return at the same time online?

Thank you.

Probably not possible to add the S TPAC with L domestic on the same ticket. Bes is to call for such changes. Is the family member hoping for a flight credit? There may also be change fees ex-Japan

Recent template ex-NRT seems to permit end-on-end (so change might be possible) but change fees are JPY 20,000. Agree that calling is better for anything complicated.

Looking at fare filings, this doesn't look possible unless maybe comparing BE fares with non-BE fares. Roundtrip L fares are within a few dollars of each other and S fares are definitely more.

Thank you. He is fine with keeping separate reservations even though there is a risk of miss connection.
Yes. He is hoping for a flight credit.

Thank you. He asked me over the phone so I do not remember the exact booking classes. Current booking class might be V or W and he is looking for T or L or K for NRT-SFO. He mentioned the cost difference would be around $200 saving in total. I said NO to United domestic + United international with 1 hr connection in SFO on two separate bookings for $200 savings.

From what you've posted above, your family member is not keeping separate reservations, but creating separate reservations in order to obtain a lower total fare. There's a big difference.

Yes -- you should be able to change both outbound and return at the same time during an online flight change by clicking the "Change this Flight" button in both directions prior to clicking the "Continue" button. (That's the sequence on the web, anyway; the app might be slightly different). If they're going to try to use multi-city search to get all of this onto a single ticket, they should be able to click "Add another flight" twice, but they'll have to ensure that the segments are in order, and frankly I'd expect the interface to error out at some point if you were to try this. It's just not that robust.

I took a quick look at the S fares -- and other related SFO-DEN fares, since you added that the fare buckets might have been wrong -- and I don't see any with a �20,000 cancelation fee (you mention �20,000 in another post). Most of the S fares are non-refundable; if they paid extra for a refundable fare, it looks like the cancelation fee is �30,000. However, each of the non-refundable fares that I see has a �20,000 change fee. That fee will be collected for any voluntary change, making this entire exercise moot if the cost savings is only $200; after paying the change fee, you're looking at a $65 net savings at current exchange rates.

Good advice.

Agreed. If the actual desire is to end up with two separate reservations -- presumably because the domestic fare is BE or because the discount fares aren't combinable end-on-end -- then it can't be performed in a single operation. OP's family member would need to change to NRT-SFO and then purchase SFO-DEN separately.