private Entity RetrieveEntityById(IOrganizationService service, string strEntityLogicalName, Guid guidEntityId)

       {

           Entity RetrievedEntityById= service.Retrieve(strEntityLogicalname, guidEntityId, newColumnSet(true)); //it will retrieve the all attrributes

           return RetrievedEntityById;

       }

How to call?

Entity entity = RetrieveEntityById(service, "account", guidAccountId);