Do you want to (partially) cancel sent invoices or does a contact owe money? In MICE you can credit invoices easily following the two steps mentioned below.
Step 1: Go to the invoice (via billing or via the event). You are now in the invoice information screen.
Step 2: Above the invoice displayed, select 'more' and select 'fully credit' or 'partially credit'.

✔The invoice is now credited🥳
Partially credit an amount of products
Do you want to credit just a part of the total amount of a product? That is possible.
Choose partially credit and select relevant product lines. Now you can adjust the product amount or unit price.