Managing instances with Autoscaling groups - cannot detatch an instance that is in standby

Question

I get the following error when I try to detach an instance in standby from my asg:

Trying to detach instance(s) resulted in failure AutoScalingGroup .io has min-size=1, max-size=1, and desired-size=1. To detach 1 instance, please update the AutoScalingGroup sizes appropriately.

This is what the instances look like

And these are my ASG sizes:

Answer 1

I realised I needed to set it back to in-service to detach it. Looks like setting an instance to out of service is similar to detaching the instance.