What to do with Untradable item

[Odd]

You can trade it for seals by talking to your GC provisions guy, its under the expert supply tab.

[Niwashi]

You can trade it for seals by talking to your GC provisions guy, its under the expert supply tab.

At what rank does that become available? (I just know that as Sergeant Third Class, I don't have access to the expert ones yet. It's a little odd - at reaching Sgt 3rd class, the NPC dialog said that meant I'd now be eligible for more supply missions, but they aren't actually available yet.)