Address Change on Contact Record Not Reflected on Invoice to Client

Each Client has a minimum of 2 address records - primary and billing. When you are editing an address through the Contact View, the Primary address is the default address.  The Users must also change the Billing Address.  Changing one address does not automatically change the other address.  Assuming they have the rights to change the Billing address, they need to call up the Contact record for the Client, click on the red down arrow to the right of the word Primary and choose Billing.

Change the address and save it.  You may then reprint the Invoice and it will reflect the new billing address.