There's two approaches I can think of...
DataTable dt = new DataTable();
IEnumerable<datarow> rows = dt.Rows.Cast<DataRow>().Where(r => r["Name"].ToString() == "SomeName");
rows.ToList().ForEach(r => r.SetField("Name", "AnotherName"));
foreach (DataRow row in dt.Rows)
{
if (row["Name"].ToString() == "SomeName")
row.SetField("Name", "AnotherName");
}
Of course you should replace
"SomeName"
and
"AnotherName"
with your own variables.
Hope it helps!