I sent a invoice to a customer who wasnt taking 20% off for cis after i sent the invoice the customer changed and took 20% off for cis how do I change the invoice now

Hello, craig-lees. 

Thank you for reaching out to the Community. You'll need to manually open the invoice and select the CIS rate. Once done, it will calculate and apply the CIS to this transaction.  

I'm adding these helpful articles to learn more on how CIS feature works in the program:  

• CIS in QuickBooks
• Already using CIS in QuickBooks?

Know that the Community got you covered if there's anything else you need. Have a lovely day!