This is an old revision of the document!
void ChangeFlag(str flag, bool value)
void ChangeActorFlag(int tid, str flag, bool value)
ACSUtils provides an implementation of A_ChangeFlag for ACS. Before using it, you need to add decorate/changeflag.txt
from ACSUtils to your mod.
ZDoom later added its own version, SetActorFlag, but it's not available in Zandronum 3.0.