title: Switch Amazon EC2 instance from small to large, reusing block device
body: <p>I created a small Amazon EC2 instance like this:</p>
  
  <pre><code>ec2-run-instances --group default --block-device-mapping "/dev/sda1=:16:off" \
    --instance-initiated-shutdown-behavior stop ami-cb97c68e
  </code></pre>
  
  <p>That created a fixed disk for the instance in Amazon's Elastic Block Store.  Now I find I would like to upgrade to a large instance of EC2... but I would like to continue using the fixed disk I created for the small instance.</p>
  
  <p>How do I switch it over?  (For the record, that AMI is for the US West Ubuntu image.)</p>