How to use the LIKE as a parameter in a function in postgres

Hello everyone, I am trying to pass a query that I use regularly to a function but I run into problems to create it. What I have so far is the following

CREATE OR REPLACE FUNCTION "public"."prueba" (in regional varchar, in fecha date) RETURNS TABLE(num_recepcion varchar, nombre varchar, nit varchar, nombre_ips varchar, total int4, tipificacada int4, devuelta int4, fecha_recepcion date, fecha_asignacion date, nombre_operador varchar, tipo int4) AS
'
BEGIN
  RETURN QUERY

SELECT
    TIPI."NUMERO_RECEPCION",
    TIPI."NIT_IPS",
    TIPI."NOMBRE_IPS",
    TIPI.Total,
    TIPI.Tipificadas,
    DEVUELTA.devultas,
    TIPI."FECHA_RECEPCION" AS Fecha_Entrada,
    CF."FechaAsignacion" AS Fecha_Asignado,
    TIPI."NOMBRE_OPERADOR_ASIGNADO",
    TIPI."ESTADO" 
FROM
    (   SELECT
            Y."NUMERO_RECEPCION",
            RF."NIT_IPS",
            RF."NOMBRE_IPS",
            Y.Total,
            Y.Tipificadas,
            RF."FECHA_RECEPCION",
            RF."NOMBRE_OPERADOR_ASIGNADO",
            RF."ESTADO" 
        FROM
            "t_RecepcionFacturacion" AS RF,
            (   SELECT
                    X."NUMERO_RECEPCION",
                    SUM(X.total)       AS Total,
                    SUM(X.TIPIFICADAS) AS Tipificadas 
                FROM
                    (   SELECT
                            SUB."NUMERO_RECEPCION",
                            COUNT(*) total ,
                            COUNT (SUB."ESTADO") AS TIPIFICADAS 
                        FROM
                            (   SELECT
                                    DISTINCT DRF."NUMERO_RECEPCION",
                                    DRF."NUMERO_FACTURA",
                                    DRF."ESTADO",
                                    DRF."ESTADO_RECEPCION"                                   
                                FROM
                                    "t_DetalleRecepcionFacturacion" AS DRF 
                                    JOIN "t_RecepcionFacturacion" AS RF 
                                    ON DRF."NUMERO_RECEPCION"= RF."NUMERO_RECEPCION"                                    
                                WHERE
                                    RF."FECHA_RECEPCION" = fecha AND
                                    RF."NUMERO_RECEPCION" LIKE regional||'%') AS 
                            SUB 
                        GROUP BY
                            SUB."NUMERO_RECEPCION",
                            SUB."ESTADO") AS X 
                GROUP BY
                    X."NUMERO_RECEPCION") Y 
        WHERE
            RF."NUMERO_RECEPCION" = Y."NUMERO_RECEPCION") AS TIPI 
        LEFT JOIN ( SELECT
                        rf."NUMERO_RECEPCION",
                        RF."NIT_IPS",
                        RF."NOMBRE_IPS",
                        X.devultas 
                    FROM
                        "t_RecepcionFacturacion" AS rf,
                        (   SELECT
                                SUB."NUMERO_RECEPCION",
                                COUNT(*) AS devultas 
                            FROM
                                (   SELECT
                                        DISTINCT DRF."NUMERO_RECEPCION",
                                        DRF."NUMERO_FACTURA" 
                                    FROM
                                        "t_DetalleRecepcionFacturacion" AS drf 
                                    WHERE
                                        drf."NUMERO_RECEPCION" LIKE regional||'%' 
                                    AND
                                        drf."ESTADO_RECEPCION"='8') AS SUB 
                            GROUP BY
                                SUB."NUMERO_RECEPCION")                        
                        AS X 
                    WHERE
                        rf."NUMERO_RECEPCION" = X."NUMERO_RECEPCION") AS 
        DEVUELTA 
        ON TIPI."NUMERO_RECEPCION"= DEVUELTA."NUMERO_RECEPCION"
        JOIN "t_ConsecutivosRecibidos" AS CF ON TIPI."NUMERO_RECEPCION" = CF."NumeroConsecutivo";
END
'
LANGUAGE 'plpgsql'

But it generates an error when trying to create the function, it tells me that I have an error in regional || '%' I appreciate any help.