As your needs change, you might find that your instance is over-utilized (the instance type is too small) or under-utilized (the instance type is too large). If this is the case, you can change the size of your instance. For example, if your t2.micro instance is too small for its workload, you can change it to an m3.medium instance.
Choose Actions, select Instance State, and then choose Stop.
Acho que não consegui encontrar a opção na interface do usuário, pois a instância ainda estava em execução.