Override one material of linked collection

I am linking a collection from a blendfile that has different meshes of an airplane.

I would like to change the fuselage material in the scene where I linked the collection to. I searched many different videos on youtube, I can not find a way to modify the material of the fuselage mesh.

I am using relations>Make library override

But the material has all the parameters greyed out.
Is it possible to “unlock” that ?

Thank you

Look into “library overrides”.