If you previously enabled push notification and acquired a certificate from Apple, you can change the Apple ID associated with the certificate.
WARNING: Changing your Apple ID replaces the existing certificate and disrupts notifications to registered devices. Users must reregister their iOS devices and Mac computers with the Apple Push Notification Service.
Select your server in the Server app sidebar, then click Settings.
Next to “Enable Apple push notifications,” click Edit.
Next to the Apple ID, click Change.
A warning states that changing the Apple ID disrupts existing push notifications until users reregister their devices with the service.
Read the warning, then click Continue.
Enter the Apple ID and password.
Click “Get certificate.”