How to change the identity pool id of an App in Amazon Mobile Analytics console

I have already set up Amazon's S3 and DynamoDB in an iPhone App so I have Cognito going and an identity pool with the proper roles / policies set up.

I am now trying to also use the Analytics, but cannot work it out.

I have set up an app in Mobile Analytics but According to this PDF from Amazon I can change the pool id / or set up a new app with a choice of an ID. I cannot do that.

How Do I change the pool id for an existing app set up in Mobile Analytics?