query can't merge into table of the other schema

Hello,
Would you please tell me why I can't merge table from another schema? I have granted all the privilege from one to another.
this is procedure from Oracle:\CREATE OR REPLACE EDITIONABLE PROCEDURE"CIDR_STAGING"."PR_MIG_STG_DATE_IN" (

v_Ret OUT number )

as

       v_ErrorCode             number;

       v_ErrorMsg             varchar2(512);

       v_Module                varchar2(32) := 'PR_MIG_STG_DATE_IN';

begin

 
   ----

   --MERGING: STG_DATE_IN into SC_DATE_IN

   ----

  MERGE INTO cidrdba.sc_date_in prod

  USING (

          SELECT Receipt_Number,date_in,mig_filename,mig_insert_dt,mig_modified_dt

          FROM cidr_staging.STG_Date_In

          ORDER by mig_seq

          ) stg

   ON (prod.receipt_number = stg.receipt_number )

   WHENMATCHED THEN UPDATE SET

  --   prod.Receipt_Number     =stg.Receipt_Number,

     prod.Date_In                     = stg.Date_In,

     prod.mig_filename                = stg.mig_filename,

     --prod.mig_insert_dt               = stg.mig_insert_dt,

     --prod.mig_modified_dt             = stg.mig_modified_dt

     prod.mig_modified_dt             = sysdate

   WHENNOT MATCHED THEN INSERT

          (

                   prod.Receipt_Number,

                   prod.Date_In,

                   prod.mig_filename,

                   prod.mig_insert_dt,

                   prod.mig_modified_dt

          ) VALUES (

                   stg.Receipt_Number,

                   stg.Date_In,

                   stg.mig_filename,

                   sysdate,

                   --stg.mig_insert_dt,

                   null

                   --stg.mig_modified_dt

          )

   ;

 
   ----   -- Set the return code to 0

   ----

   v_Ret := SQLCODE;

 
----

-- Exception error handler

----

exception

   whenothers then

          v_ErrorCode := SQLCODE;

                v_ErrorMsg  := SQLERRM;

 
                v_Ret       := v_ErrorCode;

 
                ----

                -- Commit the record into theErrorLog

                ----

                pr_write_error_log(sys_context('userenv','session_user'),

                                sys_context('userenv','host'),v_Module,

                                v_ErrorCode,v_ErrorMsg );

 
                ----

                -- Intentionally leaving the"commit" to application

                ----

end;

/

I converted to Postgres:
CREATE OR REPLACE FUNCTION "CIDR_STAGING"."PR_MIG_STG_DATE_IN" (v_Ret OUT integer ) RETURNS integeras $$
declare        v_ErrorCode             integer;        v_ErrorMsg              varchar(512);        v_Module                varchar(32) := 'PR_MIG_STG_DATE_IN';begin
   ----   -- MERGING: STG_DATE_IN into SC_DATE_IN   ----   MERGE INTO cidrdba.sc_date_in prod   USING (           SELECT Receipt_Number,date_in, mig_filename,mig_insert_dt,mig_modified_dt           FROM cidr_staging.STG_Date_In           ORDER by mig_seq           ) stg   ON ( prod.receipt_number = stg.receipt_number )   WHEN MATCHED THEN UPDATE SET   --   prod.Receipt_Number     = stg.Receipt_Number,      prod.Date_In                      = stg.Date_In,      prod.mig_filename                 = stg.mig_filename,      --prod.mig_insert_dt                = stg.mig_insert_dt,      --prod.mig_modified_dt              = stg.mig_modified_dt      prod.mig_modified_dt              = sysdate   WHEN NOT MATCHED THEN INSERT           (                   prod.Receipt_Number,                   prod.Date_In,                   prod.mig_filename,                   prod.mig_insert_dt,                   prod.mig_modified_dt           ) VALUES (                   stg.Receipt_Number,                   stg.Date_In,                   stg.mig_filename,                   sysdate,                   --stg.mig_insert_dt,                   null                   --stg.mig_modified_dt           )   ;

 ---- -- Set the return code to 0 ----   v_Ret := SQLCODE;
------ Exception error handler----    exception when others then      v_ErrorCode := SQLCODE;      v_ErrorMsg  := SQLERRM;      v_Ret := v_ErrorCode;
      ----      -- Commit the record into the ErrorLog      ----
--      RAISE NOTICE 'calling "pr_write_error_log"(%)',( sys_context('userenv','session_user'),PERFORM pr_write_error_log ( sys_context('userenv','session_user'), sys_context('userenv','host'), v_Module,                                v_ErrorCode, v_ErrorMsg );end;$$ LANGUAGE plpgsql;
ERROR:  "cidrdba.sc_date_in" is not a known variableLINE 13:    MERGE INTO cidrdba.sc_date_in prod                       ^SQL state: 42601Character: 352 thank you.Bach-Nga

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