Here is a way to do this in DaySmart Recreation:
On the right hand side of your page, click the "Settings" button.
On the left, click Products and then Select Products from the list of options.
Click New Product. You can call it "Customer AR Write off" or something like that.
Have the price be $-0.01 so you can modify the amount depending on what the customer is owed.
Choose whether you want to have this item on the cash register or you can just assign a UPC code to it like "ARwriteoff" that only a few people know so that this will not be used by your front desk staff.
Ring up this negative product and modify it to the amount that the customer owes. For example, if the customer's balance is currently $171 on their account, you will want your shopping cart to say $-171 credit with your new product.
Make sure the customer is invoiced in the shopping cart.
Change the Payment box to 0.00 and add a Payment note.
Press Process Check-Out.
Go back to the customer's profile page and click the "Make Payment" button under their name on the left hand side of the page. This will show all of their open invoices.
Click on the open box next to the negative invoice you just created and the amount will automatically appear. Also, click on the invoice where the customer originally owed the money so that amount automatically appears in the box. They should balance each other out if you did your math right!. Click the make Payment box.
The invoices will appear in your shopping cart and the amount should total $0. Click the Check-out button.
Type in a payment note as to why you are writing off the customer AR.
Click the "Do Not Send Receipt" box.
Hit Process Checkout.