The status of a customer (which you can see displayed on the portfolio list view as a column) is automatically calculated by Planhat based off of subscription data.
Here are the statuses in Planhat and how they are determined:
Prospect = there are no historical or future license for the account (in other words there is no subscription data for that account)
Customer = there is an active license associated with the account
Canceled = the license has churned, but the license period is still currently active
Lost = the license has been lost and the subscription period has passed and the license is no longer active
Coming = a subscription is in Planhat for that account, but the start date is in the future