Resizing instances through the amazon ec2 .net api

Im trying to modify the size of an ec2 instance from within a .net program.

E.g. set an instance from 1GB ram to 2GB etc.

The amazon documentation does not seem to have any clear explanation. http://ift.tt/1J2nY5E

Is there no simple way to do this, for example:

Instance instance = Instance.GetById(xx);
instance.SetType( "small-1.1" );