How to repay a debt

I was asking here what can be done if I have a debt, and I do not know how to find the person I owe. Praise be to Allah, I was answered. They said that it was necessary to repent and, if possible, do charity work. But I have this question. My sister owes me money. If I forgive her part of the debt, will I also be able to close the other debt? Or not? And more. Here, as a thank you, is it possible to close the debt by donating online? That is, to throw money to a certain charitable foundation?