Assuming you want to split the cell value on the space character, and add each part as a new cell:
if (c == 2)
{
string[] parts = cell.Value.ToString().Split(' ');
foreach (string value in parts)
{
PdfPCell cell2 = new PdfPCell(new Phrase(value, calibri));
pdfTable.AddCell(cell2);
}
}
If that's not what you're trying to do, or if it doesn't work, then you'll need to provide more details.