Forms :: Error / Signature FNC_GET_DET Has Been Changed

I have created 1 function as below in database

FNC_GET_DETAIL(deptid number,p_pass varchar2 default 'Y', g_count out number ) return number;

I have called this function from my forms (Test.fmb) as below:

declare
g_count number;
p_deptid number;
l_ret number;
begin
l_ret := FNC_GET_DETAIL(p_deptid,'Y', g_count );
end;

now I compiled that form in RMP schema and run in the same schema it run fine.But same function i have created on another schema and copying same fmx in that runtime and trying to run ..It wont works.It throws error : Signature has been changed.

Later on i came to know that such error occurs jus becoz of 2nd parameter p_pass varchar2 default 'Y'.