The Law Code of Devala 6.7: Smṛtitattva · Vīramitrodaya · Nirṇayasindhu +1

6.7

ekoddiṣṭe tu saṃprāpte yadi vighnaḥ prajāyate | māse 'nyasmiṃs tithau tasmiṃs tadā dadyāt prayatnataḥ

At a death or a birth, for female slaves, / and for wives taken in natural order of castes, / purification is equal to that of the master; when the master dies, it is by uterine kinship.

If an obstacle arises when the single-person śrāddha is due, he should give it carefully on the same lunar day in another month.