Add Keypair to existing EC2 instance

Question

I was given AWS Console access to an account with 2 instances running that I cannot shut down (in production). I would however like to gain SSH access to these instances, is

Answer 1

I didn't find an easy way to add a new key pair via the console, but you can do it manually.

Just ssh into your EC2 box with the existing key pair. Then edit the ~/.ssh/authorized_keys and add the new key on a new line. Exit and ssh via the new machine. Success!