I am trying to call a procedure using a trigger, so whenever a MASTER_ID is updated in one table, my procedure should be triggered, but if the Master ID is added for the first time, it should not be added.

I have written my procedure as below and is working fine, but not sure how to connect it to trigger and do I need to change the master_id variable value. Please help

My Master ID should be the id same as it has been updated.

CREATE TRIGGER ABC 
AFTER UPDATE 
ON CED FOR EACH ROW WHEN (OLD.MASTERID <> NEW.MASTERID AND OLD.ORIGINDATE = NEW.ORIGINDATE AND OLD.STATUS <> NEW.STATUS) 
BEGIN 
EXE dbo.someproc
END;

CREATE PROCEDURE [dbo].[PROC NAME]
(
    @trans_id INT, 
    @return_flag VARCHAR(1) OUTPUT,
    @error_msg VARCHAR(100) OUTPUT
)
AS 
BEGIN
    BEGIN TRY
        DECLARE @MASTER_ID INT = NULL;
        DECLARE @INFO VARCHAR(10) = NULL;
        DECLARE @AP VARCHAR(20) = NULL;
        DECLARE @AV VARCHAR(20) = NULL;
                
        SET @return_flag = 'Y';

        SELECT 
            @MASTER_ID = MASTER_ID,
            @INFO = INF
            @AP = AP,
            @AV = AV,
            
        FROM
            [dbo].Tablename 
        WHERE
            MASTER_ID = @trans_id;
        IF EXISTS (
            SELECT  1
            FROM [dbo].[table name] AS FM
            JOIN [dbo].[2ndtable] AS FP ON FM.MASTER_ID = FP.MASTER_ID
            WHERE FM.MASTER_ID = @MASTER_ID
        )
        BEGIN
            SET @STATUS = 'SEEYOU';
        END
        BEGIN
            SET @STATUS = 'SEEYOU';
        END
        INSERT INTO dbo.table (
            [COl1],
            [COl2],
            [COl3],
            [COl4]
        )
        VALUES (
            @MASTER_ID,
            @INFO,
            @AP,
            @AV,
             );
SET @error_msg = 'Success';
    END TRY
    BEGIN CATCH
        DECLARE @err_msg VARCHAR(200)
        DECLARE @ErrorNumber INT = ERROR_NUMBER()
        DECLARE @ErrorMessage NVARCHAR(100) = ERROR_MESSAGE()
        SET @err_msg = CONCAT(' ', 'ERROR', ' ', @ErrorNumber, ' ' + @ErrorMessage)
        SET @return_flag = 'N';
        SET @error_msg = @err_msg;
    END CATCH
END