Update SSRS subscription owner

USE ReportServer
GO

-- Get user ID
DECLARE @OldUser NVARCHAR(36) = (
        SELECT UserId
        FROM dbo.Users
        WHERE userName = '<domain_name,,domain>\<old_user,,windows_user>'
        )
DECLARE @NewUser NVARCHAR(36) = (
        SELECT UserId
        FROM dbo.Users
        WHERE userName = '<domain_name,,domain>\<new_user,,windows_user>'
        )

-- Validate User 
IF EXISTS (
        SELECT *
        FROM dbo.Subscriptions
        WHERE [OwnerID] = @NewUser
        )
BEGIN
    -- Update to new user
    UPDATE s
    SET OwnerID = @NewUser
    FROM dbo.Subscriptions AS s
    WHERE [OwnerID] = @OldUser
END
GO