Zombie Process

Hi Does anybody knows how to kill a zombie process? I know that the only way to kill the zombie process is when you reboot the computer, but if I couldnt do that? what other options does I have?, somebody told me that there is another way and it is sending a signal to the process zombie because it is in a state of wait4(), but I dont know it is true but if it were, how could i do that? because the parent is the init process pid 1.. regards.