Well, as long as your insurance carrier is willing to play ball, you can get those changed with them, and reconcile with the government when it gets its act together. Just be careful of grab backs if you're due a lower subsidy (in the other direction the system doesn't yet implement payments to insurers, as I understand it that'll work on the honor method with the insurers submitting invoices for subsidies with reconciliation to follow).
Yup, I read an article yesterday pointing out that in addition to those changes, it doesn't support easy edits for change in income, etc. Right now Healthcare.gov essentially assumes every enrollee will have the same exact plan from now until...infinity?