Basically you can say: One HomePilot® per Amazon account.
In case you have registered several HomePilot® on one WR Connect account, you will be asked after entering your access data which HomePilot you want to operate with the Skill.
You would have the option to deactivate the skill and then reactivate it to select another HomePilot® after entering your credentials, but since this is not really smart, we would not recommend it.