C# Online Compiler | .NET Fiddle

<no name> by Anonymous

using System;
using System.Linq;
using System.Xml.Linq;

public class Program
{
    public static void Main()
    {
        const string xml = @"<soap:Envelope xmlns:soap=""http://schemas.xmlsoap.org/soap/envelope/"">
    <soap:Body>
        <GetOrderResponseRequest xmlns=""http://www.edibulb.nl/XML/Order:2"">
            <Header>
                <UserName xmlns=""urn:ebl:edibulb:xml:data:draft:ReusableAggregateBusinessInformationEntity:2"">FBT_000390</UserName>
                <Password xmlns=""urn:ebl:edibulb:xml:data:draft:ReusableAggregateBusinessInformationEntity:2"">1FWcgwrx9</Password>
                <MessageID xmlns=""urn:ebl:edibulb:xml:data:draft:ReusableAggregateBusinessInformationEntity:2"" schemeDataURI=""8719604082016"">8719604082016100376</MessageID>
                <MessageDateTime xmlns=""urn:ebl:edibulb:xml:data:draft:ReusableAggregateBusinessInformationEntity:2"" format=""304"">20170523090413+02:00</MessageDateTime>
            </Header>
            <Body>
                <AgentParty>
                    <PrimaryID xmlns=""urn:ebl:edibulb:xml:data:draft:ReusableAggregateBusinessInformationEntity:2"" schemeID=""251"" schemeAgencyName=""EBC"">8719604178115</PrimaryID>
                </AgentParty>
                <GetOrderResponseDetails>
                    <MutationDateTime xmlns=""urn:ebl:edibulb:xml:data:draft:ReusableAggregateBusinessInformationEntity:2"" format=""304"">20170510000000+02:00</MutationDateTime>
                    <BuyerParty xmlns=""urn:ebl:edibulb:xml:data:draft:ReusableAggregateBusinessInformationEntity:2"">
                        <PrimaryID xmlns=""urn:un:unece:uncefact:data:standard:ReusableAggregateBusinessInformationEntity:3"" schemeID=""251"" schemeAgencyName=""EBC"">8719604082016</PrimaryID>
                    </BuyerParty>
                </GetOrderResponseDetails>
            </Body>
        </GetOrderResponseRequest>
    </soap:Body>
</soap:Envelope>";

        var doc = XDocument.Parse(xml);

        doc.Descendants()
            .Attributes()
            .Where(x => x.IsNamespaceDeclaration)
            .Remove();

        foreach (var element in doc.Descendants())
        {
            element.Name = element.Name.LocalName;
        }

        Console.WriteLine(doc);
    }
}

​x
 
using System;
using System.Linq;
using System.Xml.Linq;
​
public class Program
{
    public static void Main()
    {
        const string xml = @"<soap:Envelope xmlns:soap=""http://schemas.xmlsoap.org/soap/envelope/"">
    <soap:Body>
        <GetOrderResponseRequest xmlns=""http://www.edibulb.nl/XML/Order:2"">
            <Header>
                <UserName xmlns=""urn:ebl:edibulb:xml:data:draft:ReusableAggregateBusinessInformationEntity:2"">FBT_000390</UserName>
                <Password xmlns=""urn:ebl:edibulb:xml:data:draft:ReusableAggregateBusinessInformationEntity:2"">1FWcgwrx9</Password>
                <MessageID xmlns=""urn:ebl:edibulb:xml:data:draft:ReusableAggregateBusinessInformationEntity:2"" schemeDataURI=""8719604082016"">8719604082016100376</MessageID>
                <MessageDateTime xmlns=""urn:ebl:edibulb:xml:data:draft:ReusableAggregateBusinessInformationEntity:2"" format=""304"">20170523090413+02:00</MessageDateTime>
            </Header>
            <Body>
                <AgentParty>
                    <PrimaryID xmlns=""urn:ebl:edibulb:xml:data:draft:ReusableAggregateBusinessInformationEntity:2"" schemeID=""251"" schemeAgencyName=""EBC"">8719604178115</PrimaryID>
                </AgentParty>
                <GetOrderResponseDetails>
                    <MutationDateTime xmlns=""urn:ebl:edibulb:xml:data:draft:ReusableAggregateBusinessInformationEntity:2"" format=""304"">20170510000000+02:00</MutationDateTime>
                    <BuyerParty xmlns=""urn:ebl:edibulb:xml:data:draft:ReusableAggregateBusinessInformationEntity:2"">
                        <PrimaryID xmlns=""urn:un:unece:uncefact:data:standard:ReusableAggregateBusinessInformationEntity:3"" schemeID=""251"" schemeAgencyName=""EBC"">8719604082016</PrimaryID>
                    </BuyerParty>
                </GetOrderResponseDetails>
            </Body>
        </GetOrderResponseRequest>
    </soap:Body>
</soap:Envelope>";
​
        var doc = XDocument.Parse(xml);
​
        doc.Descendants()
            .Attributes()
            .Where(x => x.IsNamespaceDeclaration)
            .Remove();
​
        foreach (var element in doc.Descendants())
        {
            element.Name = element.Name.LocalName;
        }
​
        Console.WriteLine(doc);
    }
}
​

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