You can use PAGE INFO ALREADY TRANSFERRED TO THE NEW WIKI - Variable Based Events but under a few conditons.

In addition to variables with the “P_” prefix, you are allowed (on the Blueprints only) to the EVENT_ prefix, as long as the value starts by “p_”.

You can also call the UnregisterVariableEvent/RegisterVariableEvent functions, as long as the script parameter starts by “p_”.

You can only bypass (using BypassVariableEvent) your own varible events (that starts by “P_” : pf_bypassvarevnt).

The name of variable events from players scripts must start by P_, for example “P_EVENT_WANTS_HELP”.