A3 Miles & Bonus booking on UA schedule change
 

I logged onto the A3 app 2 days ago and noticed a significant schedule change that I haven't been informed about yet. I used by A3 miles & bonus miles to redeem a return SEA to GCM booking between Jan 11 to Jan 19, 2019 flying UA on all four segments.

Original booking was:
Jan 11 dep @ 16:04 SEA - 22:00 ORD / Jan 12 dep @ 10:40 ORD - 15:30 GCM
Jan 19 dep @ 17:10 GCM - 19:15 IAH / Jan 19 dep @ 21:30 IAH - 00:25 SEA

Proposed reschedule is (I still haven't accepted yet):
Jan 11 dep @ 13:45 SEA - 19:29 ORD / Jan 12 dep @ 10:19 ORD - 15:10 GCM
Jan 19 dep @ 12:50 GCM - 15:59 ORD / Jan 19 dep @ 19:35 ORD - 22:03 SEA

The biggest issue I have with the proposed reschedule is the 4 hour earlier departure from GCM on the 19th and the almost 4 hour layover in ORD.

What does Aegean or United afford to PAX in this situation? I called A3 and they don't have any other Star Alliance inventory available on the same dates to rebook me on. I called UA and they said since it's not their ticket they can't do anything to it. Would the gate agents for my outbound flight have the ability to modify my inbound routing? I see plenty of award availability on UA, but for the moment it appears they're not making it available to Star Alliance partners. Perhaps I just wait and hope that UA opens up unsold inventory closer to the departure date?

Anyone have any other thoughts or suggestions?

What does Aegean or United afford to PAX in this situation?
United to open award space on flight UA1495 in business (if you were in business), and then you call A3 to change your ticket to that flight.
By the way, why did the UA1495 flight on your itinerary change?
The original flight still shows without any changes (with eceonomy class award space) even now. See below. Can you see the same flight on a simple cash ticket search on UA.com?

[KVS Tool 8.9.9/Diamond - Awards/AC-StarAlliance/CA-Auto]

actually, see if you can select alternative flights (on UA website) rather than the one proposed by UA. Once you do, then youll need to call A3 to get the changes ticketed. (or call A3 if you need to)

I saw that the GCM to IAH is still available, however there is no available connecting IAH to SEA until the 20th. My guess is that United is not making IAH to SEA UA 438 or UA1792 on the 20th available for star alliance redemption. I am not booked in business class.

From 15:59 till 17:35 it's 96 minutes (a little more than 1.5 hours) and not four hours: one of the two big issues solved! ;)

Bugger.. It should read 19:35 not 17:35, I just edited my original post, thanks for the sharp eyes! The 4 hour layover I'm not so happy with, but moreso the 4 hour earlier departure from GCM.

UA can update your reservation, but A3 has to ticket it. If you can convince a UA agent to add the flights you want to your reservation in X class, A3 should be able to reissue your ticket to reflect the new flights.

Finally a meaningful update:

Spoke with United again. Agent explained that Aegean reservations agent needs to call United and request a protection accommodation be made on my booking due to the involuntary schedule change. Only then can an United supervisor change the booking class to X to allow a Star Alliance partner to book an alternate flight.
I then called Aegean up and relayed this information to them. They were at first confused and didn't understand the request when they called me back but the second agent I spoke to understood what needed to happen, went away and called me back about 45 minutes later saying that she could rebook me on the GCM-IAH flight leaving on the 19th, overnight in IAH and have my choice of any of the three IAH-SEA flights out on the 20th. There was a minor increase of 4 Euro/ticket in added fare collection, but I'm happily willing to pay that to get this rebooking done.