You can do it the same way as you do when you receive the repay for the whole amount of the debt. Click the debt account, in the window that opens click "Return"
Enter the name of the wallet that you get the repay to and then enter the amount that you've received. Click "+" to save.
If you click "Return" once you get repaid another part of the debt and enter the rest $140, your Debt account will be automatically closed.