Well it looks like she was the one who did the ADRs. Trust me, if you had, you would be in a similar state right now. Is there availability the day before? How do they do that? Do they just put you on the other flight or are there price differences involved?
Any major airline is very well equipt for handling this. CO has been tweaking their schedules to deal with loads and changing things now they're in the process of merging with UA. This can cause some changes and cancellations (allthough a very small % of total flights), especially when you've booked flights at 10/11 months out. Most of the times they won't go "let's have fun and scr*w everything up". They'll work with the customer where possible. Sometimes the system will automatically book you on another available flight. Might mean other times, other connecting-hub, you name it. Doesn't that fit your likings, plans or anything? Simply call the airline, DO NOT CLICK "ACCEPT SCHEDULECHANGE" ON YOUR RESSIE ONLINE! and the folks at the CO callcenter will happily book you onto a flight that fits your plans best. Price differences will not be taken into account, unless you're changing from economy to business first etc. When staying in the same class, CO will not charge a changing fee, will not charge the difference if the other flight is more expensive, but also will not credit if flight becomes cheaper.
They even go as far as offering this option free of charge -remember; normally you would have to pay to be chance flights-, with a schedule change that is relatively very little. Some airlines will stick to their rules "no free changes unless schedule change resulted in at least a 2 hour difference" with no exceptions. CO not so, in my experience. I've had them happily chance our ressie to a much more expensive flight because our scheduled one changed it's arrival time at EWR with about 14 minutes.
As a full codeshare, they can and will -if asked- rebook on a UA-flight, allthough most of the time with a CO-flightnumber. Same goes for LH. Don't know about VS as I'm not UK-based. (VS does fly from AMS, but does not come up as an option, same as with UA before the closer coöp before the merger was announced)
Same goes for seating assignment. About a month, perhaps 2 ago, CO has started a major rehab on seatingnumbers. They've done this to allign seatnumbers better for internal flights, so if a last minute equipment switch is needed, folks will still basically have their same seating number, location etc. Because of these changes, you might find some rownumbers "missing" on for instance a 764. The rows will jump from 4 (last one in BF) to 10 (first in economy).
During these changes, seatingassingments went kinda crazy. If left alone, most of those sorted themselves out in a couple of days, for some it took up to 14 days. However, folks that did chance themselves after seeing the first switchingaround will find their seatingassignment all nutsy by now as the system will have done a second switch trying to make things back to the way it was as much as possible. Nothing to worry about though, if you log into the ressie online now you can change seatingassignments yourself. Only thing folks wont be able to do is select seats that have been reserved for Elites when they don't have a status. In that case, they'ld have to wait until online check in.
Seriously, these things are very normal when booking any of the major aircarriers. All have schedule changes when they offer the option of booking 360 days out in advance. All have some cancellations when dealing with too low passengers loads. All deal with rescheduling in the process during and right after a merger.
For those folks having a near hart-attack; relax. This doesn't happen to a large % of routes, it'll be a certain route that is taken out and/or decided to have lesser flights per week. There has been a thread on the UK-board here recently about CO deciding to stop service to a UK airport, forgot which one. Might be worth having a look at.
These things can happen and CO (and many other airlines alike) will work with you to find an option that will fit your group. And as always; be in control yourself! Check your reservation like once a week on continental.com (or any airline you're flying with .com). IF there are any changes, CO will give you a warning when logging into the ressie. The changes will be in red letters, the rest in plane black. This way you can very easily see if a flight number is changed, the departure and/or arrival time, the aircraft or if there's been a cancelled flight and you've been rebooked. When you get closer to the actual flight date; check a bit more often perhaps. Most changes (especially the bigger ones) would occur anywhere from 9 to 3 months prior to travel. The closer you get to travelday, the smaller the chance of a cancellation. Within a month or closer it is very very rare.
I am just leaving that for them to organise at check in tho.
So you would get an extra day then? Hopefully that will make your better half feel better. 
Almost got a 
when seeing the prices. Makes AMS a bit better to stomach I guess. 
, your help is appreciated. And yes flying from Northern Ireland can indeed be an expensive business. In fact doing anything in Northern Ireland can be an expensive business.
