How to modify the content of the existing DataTable in C#?

Let said the existing DataTable dt has some existing value in column "A" and "B" at first row (Rows[0])

so,

dt.Rows[0]["A"] = You new value here;
dt.Rows[0]["B"] = You new value here;

dt.Rows[0].AcceptChanges();
dtAcceptChanges();