A sample could be
Code: SQL
BEGIN
    DECLARE @GraceType varchar(10)
    IF EXISTS (SELECT ... /*EmplChangeReason with a select SQL*/)
    BEGIN
        SET @GraceType = 'New Employee'
        /* calculate the allowance based on your formula*/
    END
    ELSE
    BEGIN
        SET @GraceType = 'Updated Status'
        /* calculate the allowance based on your formula*/
    END
END
I hope it helps.