Let’s say I have a content control that already exists in the header with the name Header. To change the text of this content control I have tried the below methods

Method1

var headerParts = document.MainDocumentPart.HeaderParts;
foreach(var headerPart in headerParts) {
    var rootElemet = headerPart.RootElement.Descendants<SdtElement>().Where(test => test.SdtProperties.GetFirstChild<SdtAlias>().Val == "Header").FirstOrDefault();
    if(rootElemet != null) {
        var elementText = rootElemet.Descendants<Text>().ToList();
        var element = rootElemet.Descendants<Text>().FirstOrDefault();
        element.Text = "Text changed";
        headerPart.Header.Save();
    }
}
document.Save();

Method 2

The solution provided in this question Update Content-Control Text in Header and Footer using Open XML SDK

Both of the methods does not update the text of the content control. Am I doing something wrong? Let me know your thoughts

Package used – DocumentFormat.OpenXml(2.16.0)