Subhosting Deployments

I've been playing around with deno subhosting. I get the concept of a project and deployments in a project. I saw there is a redeploy api endpoint but it doesn't seem that you can change the code of a deployment. Is there a way to do this or is the best way to delete the previous deployment after a new deployment is successful? In this case I'm thinking of each change to a repo being a new deployment so you wouldn't want to keep the old version. Let me know if there is a better way to do this.