I'm sure there are other experts that might know how to do this in Oracle...but I would go an easier route and use a script called from (we use php)...to fetch the pdf(scp as an example) and then display it on an available web server.
I suppose it's possible to fool Oracle by making a host concurrent program that would do the scripting to fetch the file and then save it in the standard $APPL_TOP/out file_name that the output file for the concurrent program would be written too. At that point, you could view the output (I'm not sure in 12 if that is native or if you would need a tool like ghostscript to view the file).
Just some random thoughts...
Dear Yoonas ,
Yes pdf file is generated , i need to know how the report will see this file in the db server directory