I am booked late Jan YYZ-ORD-SFO. I can preselect seats on the AC flight outbound, but cannot select seats on the AC website or the UA website for the UA flight. Its a codeshare. UA gave me my UA PNR but UA.com says I cannot book seats for the flight, nor will it display a seatmap. So how do I get an assigned seat for the ORD leg. There are a lot of crappy seats on the 319. Also is it possible to get the option to pay for ex+. If I cannot be assured of an aisle on the ORD leg, I still have 20 hours or so to cancel the whole thing without penalty, and fly someone else. I am booked in T+.

You're probably out of luck for seat selection on a codeshare. AC has 3 nonstop YYZ-SFO flights a day, though; are there no cheap seats left on any of them?

Another alternative is to book your current itinerary through UA. You'll likely be unable to choose seats on the AC leg that way, but YYZ-ORD isn't a long flight.

If you let me know the date/flight # I can pull up the current seat-map for you. You may get farther calling UA directly? Normally if you can't get a seatmap; its a couple of things a) possible equipment change b) E- is full.

Hi Denverhockeyguy.
It's UA 153 01/20. Showing lots left in Y. Does not show E+ even if inquire by requesting a refundable ticket. I wonder if I am one of those taken seats in Y.
I am showing confirmed on both the AC and UA websites, just says no seats available. If I knew how useless the AC booking site is turning out to be when it comes to code shares I would not have bothered. It seems as if UA treats codeshare pax as second class flyers.

E+ is invisible regardless of fare purchased. You must be a UA elite or have E+ access.

E+ is mostly open, but there are also a bunch of aisles and windows open in E-. Call UA, they should be able to get you an aisle or a window.

Don't beleive AC can get a seat assignment on a codeshare via aircanada.com. Call UA, and if you get a good agent, they can give you a Y seat. Have your UA PNR ready for them. If the agent says they can't do it - call back, and repeat until you find one that can. I recently had this done, though took a while for the agent to figure out how to do it. My guess is the ICC may have trouble with this, so try to get to a US-based call center.

I just pulled up a seatmap for that flight as a UA premier, and see lots open in both E and E+.

You may choose to blame AC, but the UA agent has to know how to do this and not refer you to AC. This has been discussed over the years ad-nauseum: No matter how much goodwill, effort and seeming brilliance or kindnesses by AC agents, you will not be able to confirm a seat on AC metal when booked as a UA flight number UNLESS you find a UA agent who knows how to generically request (aisle or window, for example) a seat for "their" flight via "their" PNR; and even then the response is not instantaneous. If you are told otherwise, you may feel placated and happy, but be prepared for possible disappointment when you checkin (if it truly matters to you for such a short flight).

My interpretation is the OP booked through AC, on Aircanada.com and has seats on the AC-operated, AC-coded YYZ-ORD leg, and wants seats on the UA ORD-SFO leg (AC flight number, I assume), but can't do that online. However, this can definitely be done by UA (not sure if AC can do this).

I know that I was recently able to do this, booked on AC flight number but UA equipment, called UA to get E+ assignments, as AC could not provide this. Seats were assigned instantly, as I checked my itinerary on UA.com right after the call, and my E+ seats, as described on the phone, were selected. So this can definitely be done.

After 3 trys I found somebody in India who could confirm a seat in Y.
However all the agents say they could not book an E+ seat since I had not booked on the UA site or had status. The lesson I learnt is that It does not pay to book code shares on UA through a star alliance partner, since some of the booking featurs are blocked. I am not sure if Oneworld or Skyteam operate the same way. UA did say I could check for E+ on the day of flight, but I could not do it via web check in as, I could opnly do web check in via the AC site. I wonder if I could upgrade to E+ at YYZ since the counters are next to each other, The agent says I could only do it at the RCC or the gate at ORD.
It's a 4:45 flight so the extra room would be welcome.