I am currently building our CRM on a sandbox instance. I am aware that I can change the Sandbox site to a production once I am ready to deploy. This is what I plan on doing. My question is, say a few months from now we want to make changes to the production instance. I copy the production to a new sandbox and make a few changes, in the meantime the production instance is still being used. How do I then push my new changes to the production instance, including all of the data that has been imported into prod since the changes started?