<Operation name="AddDashes">
        <!--logic to add dashes to user inputted text-->
</Operation>

<field id=CustomerSSN>
    <switch>
        <case comment="Data properly formatted">
            <text/>
        </case>
        <case comment="Data not properly formatted">
            <input>
                <Operation ref="AddDashes"/>
            </input>
        </case>
    </switch>
</field>