Note: Once you revoke your Apple Push Notification service (APNs) certificate, you will no longer be able to send push notifications to your app.

To update an existing APNs certificate, you must first revoke the certificate before generating a new one. 

To revoke an existing APNs Certificate:

1. Sign in to your Apple developer account.
   
   
2. Click Certificates, Identifiers & Profiles. Click Certificates and then under Certificates, click Production.
   
   
   
     
     
3. Click on the APNs Production iOS certificate you wish to revoke. If you have numerous certificates, you can search for the APNs certificate corresponding to your specific app using the app's Bundle ID. Click here for more information on finding your app's Bundle ID.
    
4. Click Revoke.
   
   
5. Click Revoke to confirm that you want to revoke the certificate.
   
   
6. Once you have revoked your APNs Production iOS certificate, create a new certificate and upload it to your app. See How do I generate a new Apple Push Notification Service (APNs) Certificate? for more information.