Get/Save Seasonal Address Procedure

CREATE PROCEDURE [dbo].[cust_CCIW_get_save_seasonal_address]
@OrganizationID INT,
@Guid UNIQUEIDENTIFIER,
@FromMonthDay VARCHAR(4),
@ToMonthDay VARCHAR(4),
@AddressLUID INT = -1

AS
BEGIN

    IF @ToMonthDay != ''
    AND @FromMonthDay != ''
    AND LEN(@FromMonthDay) = 4
    AND LEN(@ToMonthDay) = 4
    BEGIN
        UPDATE core_person_address
        SET from_month_day = @FromMonthDay,
        to_month_day = @ToMonthDay
        FROM core_person P
        JOIN core_family_member M1 ON M1.person_id = P.person_id
        JOIN core_family_member M2 ON M1.family_id = M2.family_id
        JOIN core_person_address A2 ON A2.person_id = M2.person_id
        WHERE P.guid = @Guid
        AND A2.address_type_luid = @AddressLUID
    END

    IF (@ToMonthDay = '' AND @FromMonthDay != '')
    OR (@ToMonthDay != '' AND @FromMonthDay = '')
    BEGIN
         SELECT 'Please input both To and From dates' AS 'Error Message'
    END
    ELSE IF (@ToMonthDay = '' AND @FromMonthDay = '')
    BEGIN
    SELECT CPA.* FROM core_person P
       JOIN core_person_address CPA ON P.person_id = CPA.person_id
         WHERE P.guid = @Guid
         AND CPA.address_type_luid = @AddressLUID
    END
    ELSE IF (LEN(@FromMonthDay) != 4 OR LEN(@ToMonthDay) != 4)
    BEGIN
         SELECT 'Unsupported date format' AS 'Error Message'
    END
    ELSE
    BEGIN
    SELECT CPA.* FROM core_person P
       JOIN core_person_address CPA ON P.person_id = CPA.person_id
         WHERE P.guid = @Guid
         AND CPA.address_type_luid = @AddressLUID
    END


END