How to replace public SSH keys on your AWS EC2 instance

Security can be easily overlooked when building a product, especially when working with an outsourced engineering team. You want to trust them, so you give them access to your servers. But then you discover fraudulent activity, and, well, you start to panic.
In hindsight, you realize you never should have shared your Secure Shell (SSH) key, instead storing it in a vault with restricted user access. If, however, someone has a private SSH key to your Amazon Web Services (AWS) Elasti