How to create and delete Blackboard entries in code?

I’d like to know whether it’s possible to create and delete a Blackboard entry entirely in C++ without going into the Blackboard editor.
I have a Spline Actor (a class that I created) that holds 1) a SplineComponent and 2) another Actor that can be spawned on the SplineComponent at any location by calling a function, calling another function will make it run along the Spline.
Anytime an actor spawns on a Spline, it should create a Blackboard entry and if the actor gets de-spawned, the BB entry should be deleted.
That is so that I can make an AI character follow the Spline using the Behavior Tree’s “MoveTo” node by actually making him follow an invisible actor that is running along the Spline.
If I have multiple Spline Paths and AI characters running around, I don’t want to create a BB entry myself for each Spline I put into the world.