If a woman would not perform ablution when having discharge due to ignorance of the ruling (of the obligation of doing so), what should she do?

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu 'alyhi wa sallam, is His slave and Messenger.

Shaykh Ibn ‘Uthaymeen said: "She should repent to Allaah The Almighty and ask scholars about this matter." For more details, refer to Fatwa 107530.

Allaah Knows best.