It is said, O king, that the Shraddha perforined in honour of the departed Manes is performable afterwards. But this general rule has a special restraint.
अन्वाहार्ये महाराज पितॄणां श्राद्धमुच्यते। तस्माद् विशेषविधिना विधिः प्रथमकल्पितः॥