Suppose we have the following contacts with the following ids: 1, 2, 3
This call would delete contacts 2 and 3
<request method="client.update">
<client>
<client_id>1</client_id>
<contacts>
<contact>
<contact_id>1</contact_id>
</contact>
</contacts>
</client>
</request>
This call would delete contact 1
<request method="client.update">
<client>
<client_id>1</client_id>
<contacts>
<contact>
<contact_id>2</contact_id>
</contact>
<contact>
<contact_id>3</contact_id>
</contact>
</contacts>
</client>
</request>
This call would delete contact 1, but create a new one as well
<request method="client.update">
<client>
<client_id>1</client_id>
<contacts>
<contact>
<contact_id>2</contact_id>
</contact>
<contact>
<contact_id>3</contact_id>
</contact>
<contact>
<first_name>Chris</first_name>
<last_name>Richard</last_name>
</contact>
</contacts>
</client>
</request>
This call would delete ALL contacts, but create two new ones
<request method="client.update">
<client>
<client_id>1</client_id>
<contacts>
<contact>
<first_name>Chris</first_name>
<last_name>Richard</last_name>
</contact>
<contact>
<first_name>Nox</first_name>
<last_name>Dineen</last_name>
</contact>
</contacts>
</client>
</request>
This call would delete all contacts
<request method="client.update">
<client>
<client_id>1</client_id>
<contacts/>
</client>
</request>