You couldn't do anything. [She's... honestly not sure if she should mention it was Korra's bending they were trying to restore. She decides to not confirm unless Katara asks. It's weird enough to say "you" when the girl next to her is younger]

You told us that... and Korra was distraught. She ran off [yep yep leave out the MaKorra] into the snows and ended up somewhere to think. When she came back [with Mako] She'd finally connected with the other Avatar Spirit. Avatar Aang had taught her how to reverse Amon's removal, and it used the Avatar State. But to be honest I don't know all the details. [Korra acts on instinct. Even if she had asked there's no way Korra would have been able to explain it]