How to increase the constraint value for PK_SortCodes_1 automatically after checking the existing value

IF  EXISTS (SELECT * FROM sys.indexes WHERE object_id = OBJECT_ID(N'[dbo].[SortCodes]') AND name = N'PK_SortCodes_1')
ALTER TABLE [dbo].[SortCodes] DROP CONSTRAINT [PK_SortCodes_1]
GO

ALTER TABLE [dbo].[SortCodes_BCP] ADD  CONSTRAINT [PK_SortCodes_1] PRIMARY KEY CLUSTERED
(
    [ID] ASC,
    [Sortcode] ASC
)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, SORT_IN_TEMPDB = OFF, IGNORE_DUP_KEY = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]
GO