How to update the Header field value by a detail field value in EDR container.

Hi All,

I want to update the Header field value by a detail field value in EDR container.

I have tried with different options in iscript for example like:

String svc_type;
function onDetailEdr
{

svc_type =  edrString(DETAIL.A_NUMBER);
logStdout("This field is of type in detail: "+ svc_type + "\n"); (value is printing as 0044123456)
}
function onHeaderEdr
{
edrString (HEADER.BATCH_ID) = svc_type;
logStdout("This field is of type in header : "+ edrString (HEADER.BATCH_ID) + "\n");(nothing printed for this)

}
function onEndEdr
{
logStdout("This field is of type in end: "+ svc_type + "\n"); (value is printing as 0044123456)

edrString (HEADER.BATCH_ID) = svc_type;