question: Find the names of customers who have used either the service "Close a policy" or the service "Upgrade a policy".
#1 return customers 
#2 return services used of  #1 
#3 return #1 where  #2 is  Close a policy  
#4 return #1 where  #2 is  Upgrade a policy  
#5 return #3 or  #4 
#6 return names of  #5