Tags array varable in actor classes is exposed direcly to blueprint
AActor | Unreal Engine Documentation (Search for “Tags” you can see blue note icon which means it exposed to blueprint)
Actor class is related to all actors so you can access varable either from Verable tab somehow (i’m not blueprint user really and i can’t turn on editor right now, there should be option to include inherent varables from parent classes, try to search) or from “Self” node. To access varbale direcly from object node (like “Self”) drag a object pin link and drop it in empty space, in context menu go to “Varables” categoty and there you should have all Set and Get of object varables, and search for “Get Tags”.
Once you gain access to Tags array, you simply remove tag from that array 
you can also add tags by adding them to that array