It is not possible to upgrade/downgrade the AWS Instance type of the workers after I created the cluster.
Today, the only way to do that is destroying and create a new cluster.
I'd love to have this feature implemented.
I am glad to hear it.
We are working on introducing Cluster API which supports Node Pools and mulitple instance types. This will help with changing instances after a cluster is running.
You won't be notified about changes to this idea.