>> Ticket is attached. Any chance of us being able to change the ticket....perhaps at nominal charges?
The conditions printed on your ticket say:
"Ticket holders can travel on the train shown or in the next 4 hours"
So it seems to me that you could use this ticket on the 11:23 train from Milano Centrale to Brig, but you would need a seat reservation from Milano Centrale to Domodossola as well, at additional cost.
I don't know anything about Italian train tickets though, and I am not sure whether a ticket bought for a regional train is also valid for a EuroCity train. Your originally-selected 9:29 train is a regional train, but the 11:23 train is a EuroCity train. Hopefully someone else will know the answer to that.
The conditions printed on your ticket also say "A single change to ticket date and time is permitted before 23:59 on the day prior to travel at Trenitalia offices ... etc"
So it seems you could get it changed in Milano the day before if you wanted to.
>> - from Milan to Domodossola (with this new purchase ticket)
- before transit in Brig to Zermatt, using our Swiss Travel Pass Flex. Just to confirm we don't have to do anything or get or pay for anything additional, other than producing our Swiss Travel Pass Flex, if requested on board by train master/conductor?
You will need the following:
1. Your ticket for the journey from Milano Centrale to Domodossola (existing ticket is probably OK, as mentioned above)
2. A seat reservation Milano Centrale to Domodossola (which you will need to buy at additional cost)
3. Your Swiss Travel Pass Flex (with 31 May 2017 filled in as a travel day)
4. You should have your passport handy in case the conductor asks for ID.
This is what you do to travel to Zermatt, starting with the 11:23 train from Milano:
1. Get on the train at Milano and don't get off until Brig.
2. For a ticket check between Milano Centrale and Domodossola, show the conductor your ticket for this sector.
3. For a ticket check between Domodossola and Brig, show the conductor your properly completed Swiss Travel Pass Flex.
4. Change trains at Brig and continue to Zermatt. You will arrive in Brig on Platform 1, walk out of the station building into the adjacent street and cross the road to Platform 14 for the Matterhorn-Gotthard trains on the other side of the road. This usually takes about 7 minutes. You have 11 minutes. Your Swiss Travel Pass Flex continues to be valid for the remainder of this journey of course, but you will have to show it again on the train from Brig to Zermatt.
Your screenshots for the 11:23 service from Milano Centrale to Zermatt via Brig are correct.
I hope that resolves your doubts.