const string sql = "select ID, MyDate, MyName  from MyTable where  ID = @ID";
const string upd = "UPDATE MyTable SET MyDate = @MyDate WHERE ID = @Original_ID";
...
public FbDataAdapter da = null;
...
    da = new FbDataAdapter(sql, cn);
    da.SelectCommand.Parameters.Add("ID", FbDbType.Integer);
    da.SelectCommand.Parameters["ID"].Value = id;
   
    da.UpdateCommand = new FbCommand(upd, cn);
                try
                {
                    da.Fill(dataSet, "MyTable");
                }

   da.Update(dataSet, "MyTable");

da.UpdateCommand = new FbCommand(upd, cn);
da.UpdateCommand.Parameters.Add("@MyDate", FbDbType.Time,  4 , "MyDate");
da.UpdateCommand.Parameters.Add("@Original_ID", FbDbType.Integer,  4 , "ID");

UPDATE MyTable SET ID = @ID, MyDate = @MyDate WHERE ID = @Original_ID