As a general rule any refund/rebooking always has to be done via the agent who supplied the tickets. Which should be obvious to any travel-agent (I have been that also in long time past).
The best hing is to check on the sncf (=French sate railways, notorious for many strikes for minor reasons-they call it ´mouvement social´) site which other trains may run-there may be a need to change enr-oute and plan accordingly.

@mcadv - I am the travel agent, but I have not ever purchased rail for my clients before. I have always used a vendor. In this case the vendor I was working with has stopped booking rail and the client was rebooking a COVID canceled trip. As I mentioned that I purchased this rail through Eurail, thus my thinking was that I need to go back to Eurail for the refund. In any case because it is very difficult to get assistance, I also went to SNCF which was difficult because all of the customer care pages on their site are exclusively in French and I don’t speak it. The journey was scheduled for the 17th so I am hoping that I am able to get a refund. My clients were only able to travel today. Forgive my ignorance of the process, but that is why I come to the community for guidance.

Eurail sells reservations but it doesn't necessarily mean they also do refunds and changes. The confirmation mail you received after buying the reservation should have information about that.

As far as I can see, the SNCF website is also available in English but if some pages are not, just use the translation feature in your browser.

Hello,

I found this link to request a refund, perfect in English. Good luck!

You can easily submit an application online.

https://www.tgv-lyria.com/fr/en/manage-your-train-booking/exchange-refund

@Sven Thank you. I was not able to submit my application online. It did not recognize my booking number. Is this because I purchased the seat reservations through Eurail? I am thinking that if I paid Eurail, then I would have to request a refund from Eurail. @Nanja are you able to guide me?

Hi Robinbar59, you can request your refund via the reservations overview in your account. For more information, have a look at the bottom of our refund page. If you need any further information/assistance on refunding your reservations, you can reach out to our Customer Support here. 

This process seems to me for a refund voluntarily initiated by the pass user, implied by the statement that the normal refund policy is applicable (and a refund may not be possible) and must be done before departure. In this case, however, the operator initiated it by cancelling the train, in which case a complete refund is always possible, also after departure time of the train.

That's right. In case you cannot get in touch with the carrier to request the refund, our Customer Support can be contacted to assist.