Command pattern in Unet

I currently have a game where I use the command pattern. So every action the player can do is encapsulated as an object, all implement the Command interface.

I now want to send each command over the network. So thought, easy, I just make a method:

But this doesn't work, because you can't have interface-types as parameters. Also note that 'Command' is my interface, while '[Command]' is...

Command pattern in Unet