I figured it out. You can just modiy the object and set it back and databind it. Below shows how.
/// <summary>
/// Gridview Row Data Bound
/// </summary>
protected void grdvOffers_RowDataBound(object sender, GridViewRowEventArgs e)
{
// Converts the UTC date to PST timezone
if (e.Row.RowType == DataControlRowType.DataRow)
{
Offer offer = ((Offer)e.Row.DataItem);
offer.Created = TimeZoneInfo.ConvertTimeFromUtc(offer.Created, CFrmFunctions.GetPresetTimeZone());
e.Row.DataItem = offer;
e.Row.DataBind();
}
}