I am trying to rename my form fields in a pdf document. The "PdfField" class has a property called "Name" which I have changed but nothing is changing in the rendered pdf. I have tried to change other properties of the PdfField such as Color and Value and that seems to work. But I have no idea why the changing of the name don't work. Here is my code:

doc = new PdfDocument(pdfFileName);

var field1 = doc.Fields["Produkt"];
field1.Color = Color.Blue;
field1.Value = "Hej";
field1.Name = "New Name";
field1.Modified();

var field2 = doc.Fields["ISIN"];
field2.Color = Color.Red;
field2.Value = "Hejdå";

doc.Save(newFilePathName);

Does anyone know why the name is not changing?