It is permissible to waive part of a debt in return for bringing forward repayment.

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Check below answers in case you are looking for other related questions:
Should he claim bankruptcy so that interest charges will be waived from him?
Ruling on buying by hire-purchase

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Related Answers:
Delaying repayment of a bank loan so that they will waive the interest
Borrowing money from one whose income comprises haram money
He owes a debt to the company and he wants to pay it off with the lump sum he receives for retirement
Should he claim bankruptcy so that interest charges will be waived from him?
Ruling on buying by hire-purchase

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