Ibn Sirin (may Allah have mercy on him) narrated from Qadi Shurayh (may Allah have mercy on him): That the woman forgoes, that is, she gives up half of her dowry, or the husband forgoes, that is, he pays the full dowry.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصداق / 14449