Sayyiduna Abu Sa'id (may Allah be pleased with him) said: My sister wanted to seek khul' from her husband, so she came with her husband to the Prophet (peace and blessings be upon him) and mentioned it before the Prophet (peace and blessings be upon him). He (peace and blessings be upon him) said: "Will you return his garden to him so that he divorces you?" She said: Yes, and I will give more as well. He (peace and blessings be upon him) said a second time: "Will you return his garden to him so that he divorces you?" The woman said: I will give more as well. He (peace and blessings be upon him) said it a third time, and the woman said: Yes, and I will give more still. So he granted her khul', and she gave the garden and something more to her husband.
The mursal hadith is more authentic.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب القسم والنشوز / 14850