Hello ​@Pauly1955 

It is not possible to answer this question without knowing your itinerary, it depends of the country and the type of train. 

Sorry Danihel  -thanks for your reply 

I am going from

St Pancreas - Lille 

Lille -Toulon 

Toulon -Avignon 

Avignon - Paris 

Paris - St Pancreas 

So  all within France .

​@Pauly1955 

I don’t think that St Pancras is in France…

If seats are available, you can exchange the reservations for the Eurostar between UK and France, but you have to pay a fee (I think 20 €). You can make these changes directly on the Eurostar website after importing the tickets.

In France, you can cancel the reservations, obtain a full refund, and buy new ones, but the price can be higher (TGV: 20 € instead of 10 €).

I would buy such reservations on raileurope.com to avoid the fees from Interrail.

Hi 

that’s great thank you for this info

cheers

SNCF reservations can also be exchanged in the TGV Inoui Pro app. You can also choose your seat from a seat map there.

​@rvdborgt 

Thanks for this information. Very useful for last minute changes. But I guess that reservations are no more refundable by the original vendor after this exchange. For an early exchange I would prefer a cancellation and a new booking. 

It is maybe also possible to cancel the reservation in this app, but you will probably obtain a SNCF voucher.

Maybe. I haven't tried that yet.

Why would you think that? That would be against the conditions.

I know that Trenitalia tickets are no more refundable by the original vendor after an exchange in Trenitalia app, I already tested it. I think that it is the same for SNCF tickets.

I already made a cancellation on a SNCF vending machine and got a voucher, but I don’t remember if it was an Interrail reservation or a SNCF ticket.

TGV reservations are fully refundable up to 30 min after departure, I don’t think that it were against the conditions to reclaim a refund in this app and obtain a voucher, but I don’t know if it works. 

A refund is a refund, not a voucher.

A refund via Rail Europe works fine; I've done that more than once. Even last minute after departure (but ot more than 30 min. of course).