To edit part-level prices in a quote, utilise the "Adjust" feature.
The 'Adjust' feature available on each part
To increase a part's price, input a positive value in either the currency or percentage field. The fields are interconnected, so as the quote calculates, you'll witness the corresponding change in the other field.
Actions button wPrice adjusted by $10 or 23%
Price adjusted by -$10 or -23%
Adjustments can be viewed in the 'Price Totals' container on the bottom right-hand side of the quote screen.
The adjustment amount viewed in the 'Price Totals' container
The Adjustment values are added to the total value of a quote but are not visible as a separate line in any of the customer-facing documents.