How To: Create A Table That Only Allows NULL Fields To Be Updated.

I need to create a table that only allows fields to be updated if the field value is NULL. Is there anyway to configure a table in this manner?

In the example below the record will be created with a serial number and verification ready flag set to true. Other processes down stream will update the remaining fields as needed but should not update fields that have already been initialized.

Table Definition

USE [DB_AUTOMATED_PACKAGING_SYSTEM]
GO
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
SET ANSI_PADDING ON
GO
CREATE TABLE [dbo].[TBL_LABEL_VERIFICATION](
[SerialNumber] [varchar](50) NOT NULL,
[VerificationReady] [int] NOT NULL,
[VoidLabelImage] [image] NULL,
[VerifiedBy] [varchar](50) NULL,
[VerifiedDate] [datetime] NULL,
[Verified] [int] NULL,
CONSTRAINT [PK_TBL_LABEL_VERIFICATION] PRIMARY KEY CLUSTERED
(
[SerialNumber] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY] TEXTIMAGE_ON [PRIMARY]

GO
SET ANSI_PADDING OFF