New assembly not loaded in adp.net application.?

Question

Hi Frnds,

I am create an assebly and installed in GAC folder, refered in asp.net application,

the problem is i change a fuctionality in assembly dll it will not reflect in client application, once i rest the IIS then only the new DLL chnage reflect 

in client application.

EG : old fuctionlaity in GAC Dll 

Function optration()

{

return(5+ 50);

}

New functinality 

Function optration()

{

return(5 - 50);

}

when call operation in ASP.net application old functionality only coming.

How to solve..

Thanks in Advance.