There are various ways to interchange and manipulate variables. One way is using "Send Message" to manipulate a value by starting a function.
just define a function in your script.
public void myfunction () {
// do something
}
then you can use Send Message with "myfunction" in method name.
Also you can receive variables with send message
public void myfunction (bool mybool) {
}
To send a bool value to a function just choose bool from parameter.
And to return a value from the function you can use
FsmVariables.GlobalVariables.GetFsmBool ("mybool").Value = true;
remember to define "mybool" from global variables.
There are other ways, this is just one of them. Also remember to include:
using HutongGames.PlayMaker;