For tax purposes, you can only merge addresses within the same tax jurisdiction:

• If the addresses are set up for tax validation in Geography Hierarchy then the address elements with a tax validation usage must match. See: Managing Validations.

  For example, Address 1 is created in a country that is set up with City, County, and State selected for tax validation. Address 2 is created in the same country. To merge these two addresses, the city, county, and state for both addresses must be exactly the same, as validated against geographies set up in Geography Hierarchy.

• If the addresses are not set up for tax validation in Geography Hierarchy, then you can merge the addresses as long as the country is the same.

• If you have both types of addresses, with and without addresses set up for tax validation in Geography Hierarchy, then you cannot merge the addresses.