How to use the default value for substitution

Provide a value for Default value for substitution. This value is placed between the leaf elements—the elements that don't have any child elements.

Note: The substitution won't work if these leaf elements are contained within an array that does not exist in the incoming documents.
Select the Use default value for substitution property.

Incoming document:
Here, the session_id element doesn't exist in the incoming document. In this case, using Default value for substitution will give us the following envelope:
```
<?xml version="1.0" encoding="UTF-8"?>
    <SOAP-ENV:Envelope xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/"
                       xmlns:ns0="http://api.clickatell.com/soap/webservice">
            <SOAP-ENV:Header />
            <SOAP-ENV:Body>
                <ns0:ping>
                    <session_id>NO VALUE</session_id>
                </ns0:ping>
            </SOAP-ENV:Body>
    </SOAP-ENV:Envelope>
```
Note:
If you don't specify the Default value for substitution and don't select the Use default value for substitution property, the elements will be removed from the envelope recursively.