Save pdf file embedded in web response

I am using webclient to send the request to get a PDF file.

byte[] response = client.UploadData(ClientUrl, Data);

My response schema is as follows. I want save the file as PDF. Could you please point me to a code sample.

I use string s = Encoding.UTF8.GetString(response); to get other fields, but not sure how to save the file.

<?xml version="1.0" encoding="utf-16"?>
<xs:complexType name="getPDF">
    <xs:sequence>
        <xs:element name="return" form="unqualified" minOccurs="0">
            <xs:complexType>
                <xs:sequence>
                    <xs:element name="status" type="xs:string" minOccurs="0"></xs:element>
                    <xs:element name="appPdfDoc" type="xs:base64Binary" minOccurs="0"></xs:element>
                    <xs:element name="messageList" minOccurs="0">
                        <xs:complexType>
                            <xs:sequence>
                                <xs:element ref="tns:Message" minOccurs="0" maxOccurs="unbounded"></xs:element>
                            </xs:sequence>
                        </xs:complexType>
                    </xs:element>
                </xs:sequence>
            </xs:complexType>
        </xs:element>
    </xs:sequence>