There are many ways to do it, but first of all, what would be the output if the state reaches the end? or what happens if it is ended?
You could set bool_ThisStateIsEnded is true on the active FSM (The one you wanted to end) at the final state and put Bool Test action (Get FSM Bool) on the other FSM that is waiting for that FSM to end.
or you could use the Send Event > name it eg: "STATE END" at your final state
and on your listener FSM state, use add event > Global Event and pick the event "STATE END"
Good Luck