How to Unregister or Update Registered SharePoint app

To get your app registration details use below link

{SiteUrl}/_layouts/15/appinv.aspx

Then update your details using below link with existing Client ID(do not use generate client ID and client secret)

{SiteUrl}/_layouts/15/appregnew.aspx

This will update your app registration details for existing client ID.

Use link for more details https://msdn.microsoft.com/en-us/library/office/jj687469.aspx

Not official/documented way but it works for me for SharePoint Online

1) I have installed Azure AD PS

2) Then run the following PS script Connect-MsolService $appPrincipal = Get-MsolServicePrincipal -ServicePrincipalName client_id Remove-MsolServicePrincipal -ObjectId $appPrincipal.ObjectId

3) Then go to {SiteUrl}/_layouts/15/appinv.aspx and try lookup app by client_id. You can get Unexpected error or no info(like new id)

4) Then go to {SiteUrl}/_layouts/15/appregnew.aspx and register app again with same client id