You can use KLM miles to upgrade without fee if there's space available to KLM for the upgrade. You just have to contact KLM and play by their rules. Your status with KLM won't get you domestic upgrades though and besides that CO Plats normally don't get upgraded on the EWR-LAX route because of the number of paid F customers. If you flew on NW within the US they would give you the upgrade, but unless something has changed while I've been not traveling for the last month or two (sucks breaking both arms and wrists!) CO will NOT give you an upgrade.