Hey guys, thanks for your responses, and sorry I was vague in my post.
I bought a train ticket through the OMIO App, I see now I should have just gone straight to the Eurostar website, but what is done is done. It is for a Eurostar from London to Brussels, transfer to a regional train in Brussels and then on to Rotterdam.
I have a Flex-type ticket and should be able to either change it or be partially refunded, but again, the OMIO App times out or "craps out" when I try to do this. The AI customer service is no help, and there is no phone number to call.
I have a transfer in Brussels, but I see on the Eurostar website that there is a faster direct train from London to Rotterdam, which I would like to travel on instead of the Eurostar to Brussels, with a transfer to a regional train to Rotterdam.
I will be traveling solo, so I just want to make this process easier and avoid waiting around in Brussels for an hour.
I tried to cancel the ticket on the Eurostar website for the first portion of the journey, but it won't let me since I used the OMIO App.
I looked into it and if I just "eat" the money from the first ticket, I can just buy the direct ticket and the original ticket will just be a no show? Is this true even if I already have the first portion of the ticket on the same train? I don't want to have an issue when I show up to the station in London.
I hope this is more clear, thanks again for the responses.