Diagnosis
There are multiple addresses for the business partner in which theexternal address number was not entered. As a result, you cannot usedirect input to change these addresses.

System Response
Error message: the change copied is not carried out

Procedure
Change the business partner in the SAP system (online) and enter theexternal address number for the addresses. You can then change theaddresses by specifying the external address number or by using directinput.