SQL> -- create a function in a remote database
SQL> connect mike/lion
Connected.
SQL> create or replace function fun_today return date is
  2  begin
  3    return sysdate;
  4  end;
  5  /

Function created.

SQL> -- create a database link and a synonym 
SQL> connect scott/tiger
Connected.

SQL> create database link dbl_ora10_r
  2  connect to mike
  3  identified by lion
  4  using 'ora10g';

Database link created.

SQL> select 'x' from dual@dbl_ora10_r;

'
-
x

SQL> create synonym syn_fun_today for fun_today@dbl_ora10_r;

Synonym created.

SQL> select syn_fun_today from dual;

SYN_FUN_
--------
11.08.07

SQL>

CREATE SYNONYM syn_cm_sp_monthly_cont_proc_pdf FOR
  cm_sp_monthly_cont_proc_pdf@cms;

function AfterPForm return boolean is
  p_errcd  number := 0;
  p_errmsg varchar2(100) := NULL;
begin
  syn_Cm_Sp_Monthly_Cont_Proc_Pdf(:p_calyear,
                                  :p_calmonth,
                                  'SYSTEM',
                                   p_errcd,
                                   p_errmsg);
  return (TRUE);
end;