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

Once an instance has been started, there is no way to change the keypair associated with the instance at a meta data level, but you can change what ssh key you use to connect to the instance.

stackoverflow.com/questions/7881469/change-key-pair-for-ec2-instance