Declension table of ?ṛtavya

Neuter	Singular	Dual	Plural
Nominative	ṛtavyam	ṛtavye	ṛtavyāni
Vocative	ṛtavya	ṛtavye	ṛtavyāni
Accusative	ṛtavyam	ṛtavye	ṛtavyāni
Instrumental	ṛtavyena	ṛtavyābhyām	ṛtavyaiḥ
Dative	ṛtavyāya	ṛtavyābhyām	ṛtavyebhyaḥ
Ablative	ṛtavyāt	ṛtavyābhyām	ṛtavyebhyaḥ
Genitive	ṛtavyasya	ṛtavyayoḥ	ṛtavyānām
Locative	ṛtavye	ṛtavyayoḥ	ṛtavyeṣu

Compound ṛtavya -

Adverb -ṛtavyam -ṛtavyāt