Discounting is only valid if the only issue left to resolve is money. If the prospect is still unsure about things like your service, delivery, quality of the product, etc., it’s best to resolve those first before talking about a discount.
Use language like:
“Do you have any issues on the cabinets or accessories going into the kitchen?”
“Do you have any concerns about the quality of the cabinets or counter-tops?”
“Do you have any concerns about our ability to install and service this kitchen?”
Each time the prospect voices a concern, stop, listen and address it.
Get through the list so that the prospect agrees in their own words that there are no issues in anything but the last remaining bucket (the price). Then use language like:
“So if I understand you correctly, the only issue you have is about the price”
And Voila!- you are now prepared to successfully negotiate a fair discount- but only if you get something in return.