Declension table of ?kṛtvya

Neuter	Singular	Dual	Plural
Nominative	kṛtvyam	kṛtvye	kṛtvyāni
Vocative	kṛtvya	kṛtvye	kṛtvyāni
Accusative	kṛtvyam	kṛtvye	kṛtvyāni
Instrumental	kṛtvyena	kṛtvyābhyām	kṛtvyaiḥ
Dative	kṛtvyāya	kṛtvyābhyām	kṛtvyebhyaḥ
Ablative	kṛtvyāt	kṛtvyābhyām	kṛtvyebhyaḥ
Genitive	kṛtvyasya	kṛtvyayoḥ	kṛtvyānām
Locative	kṛtvye	kṛtvyayoḥ	kṛtvyeṣu

Compound kṛtvya -

Adverb -kṛtvyam -kṛtvyāt