Setting Custom Depth on AI Character Upon Player Pickup Actor.

I am currently working on setting a custom depth for the AI Character so that it is like a power for the player.
The player is meant to interact with an item which then would trigger the custom depth on the AI character letting the player see the AI Character’s position through walls.
Right now the custom depth is set so the ai character is visible through walls but i am having trouble with setting it up to only trigger when the player interacts with the pick up item.
Any help?