//Check if the instance exists:
if(exists(process_id))

 //Fetching pre-defined local variables 
 x = process_id.x;
 graph = process_id.graph;

 //Changing variables:
 process_id.x = 3;
 
 //Same works for manually defined local variables(NOT private!)
end

//Note that when you are referencing variables in this way the process 
//you are referring to MUST exists, otherwise Fenix will crash.