Take your time, roll into the airport at noon.

Wow, that's almost twice as much as some of the software developers Boeing outsourced to got.

https://www.bloomberg.com/news/articles/2019-06-28/boeing-s-737-max-software-outsourced-to-9-an-hour-engineers

You expect AC to recognize your phone number when you call them and direct you to the right place, like every other airline?
Cmon Mr. Hamer!

The odds of AC being able to do this are about the same odds of someone collecting a $10,000 MCO from BA.
Oh, wait a minute...

Called the SE line twice within half an hour and got through right away.

Called the concierge line and it was answered right away.

All THREE times i spoke with the agent, i was speaking with new kids and no help was available, but they answered.

"Normal" AC reservations line is currently rejecting calls due to "circumstances out of their control".

Question: if I'm contemplating changes to an international itinerary is there any way to "preview' the charges online? i.e. check the fare difference for new date/route (if any) in addition to the applicable change fee.

If the booking was made on AC.com, you can pull it up and go through the "change" option. Not only has it shown accurate charges, but it actually works fairly well. Only one of my last ~5 changes has required calling in.

Thank you. Is it safely a "no purchase required" process? i.e. Can I go "to the end" to preview the charges and cancel out without any risk/change to my existing itinerary if I don't like it?

If so I'll try it out.

Concierge system currently uses caller ID. Not every agent uses it (!!!) but it is there.

Yes - Air Canada does not store your payment information on the website so you would have to provide it again to make a change. Just keep clicking through to the payment screen - there is no risk at all here.

Yes. I actually did it just yesterday to figure out what the change fee was on my ticket, which required me to get all the way to the final screen. Completely safe. It even retains any discounts that were applied.

I think res has the same access, but they tend to use it even less because there's a significantly lower probability of anything useful coming from it on that line than the concierge line (where everyone has an Aeroplan account).

That being said, the fact that it's a manual process to pull up any information is a bigger issue.

Made calls yesterday and today. SE line and answered right away. On both occasions, the agents were somewhere between useless and totally useless. Did not know the basics..... HUCA and dialled the concierge desk, got through in less than a minutes and both issues solved immediately.

Unless something has changed, I believe the SE line goes to the regular call center, you just jump to the front of the line. Someone can correct me if I am wrong.
So you are not likely to get any more knowledgeable agents on the SE line. I have had the SE desk tell me to call the Concierge line for a request and the Concierge line tell me that I should call the SE desk unless within 24 hrs of my flight since they are very busy.
Calling the SE line for upfare also has the same issue as mentioned in the Upfare thread - some agents know what to do, some want to charge a change fee and some say its not possible.