ofcourse it´s possible but note that tickets often include the reservation on trains that are reservation compulsory for railpass holders. Bestway to get seats next to each other is to book your reservation and the ticket of your friend directly with the railcompany. If you let us know some details like Origin & Destination it´s easier for us to get a more precise answer.

Thanks Seewulf for your answer.

I plan to travel 15-6 from Amsterdam via Paris to Nice.

2 persons. I am 68 year and have an Interrail pass first class 5 days in 1 month

travel friend have no Interrail pass and is 53 years old

I want to make an reservation for me (with Interrail pass first class) and my frriend (no Interrail pass)

In the IC Night 5771 I want to make an reservation for the two lowest beds (We have bad experience sleeping in the top beds)

for the trip on 15-6-2022, see below the schedule.

16:15

Amsterdam-Centraal

3u 21m

THA 9370

19:36

Paris Gare du Nord

20:51

Paris Austerlitz

12u 17m

IC Night 5771

09:08

Nice Ville

Greetings,

Herman

Should be possible; that Thalys still has Interrail seats available. The best is to call SNCF. Press #85 for English, no booking fees and reservations are sent via e-mail.  They should also be able to book the lower couchettes.

Thanks for the help, greetings Herman