// For complete examples and data files, please go to https://github.com/groupdocs-watermark/GroupDocs.Watermark-for-.NET
using (DiagramDocument doc = Document.Load<DiagramDocument>(Utilities.MapSourceFilePath(FilePath)))
{
// Initialize search criteria
ImageSearchCriteria imageSearchCriteria = new ImageDctHashSearchCriteria(@"D:\logo.png");
TextSearchCriteria textSearchCriteria = new TextSearchCriteria("Company Name");
// Call FindWatermarks method for the first page
PossibleWatermarkCollection possibleWatermarks = doc.Pages[0].FindWatermarks(textSearchCriteria.Or(imageSearchCriteria));
// Remove all found watermarks
possibleWatermarks.Clear();
doc.Save();
}