to him/her about it
Il a semblé très surpris lorsque je lui en ai parlé.
He seemed very surprised when I told him about it.
J'ai des billets gratuits dès que je lui en demande.
I get free tickets whenever I ask him for them.
— Harry Potter et le Prince de sang-mêlé (2009)
I need to talk to him about it.
Je lui en serai à jamais reconnaissante.
I will be forever grateful to him.
Je lui en parlerai directement.
I will speak to him directly about it.