After deleting the row from the indexed table, use the command below.
Delete code:

-- Delete records from the table
DELETE FROM library 
WHERE lastModified > '07-29-2024';

I am doing DB RESEED

DBCC CHECKIDENT (table name, RESEED, 1200)

But I am getting an index from the last entry that is deleted.

table structure is here

CREATE TABLE library (
    libIDX int IDENTITY(0,1) NOT NULL,
    fullName varchar(50) COLLATE SQL_Latin1_General_CP1_CI_AS NULL,
    lastModified datetime DEFAULT '1970-01-01' NOT NULL,
    isHidden bit DEFAULT 0 NOT NULL,
    CONSTRAINT PK_library PRIMARY KEY (libIDX)
);

What wrong I am doing here?