Not sure if I understand the question correctly but if you want to prevent the tick from reoccurring, you can use
Timer.Stop Method (System.Windows.Forms) | Microsoft Docs[
^] to halt the timer before you do anything else. Something like
private void timer1_Tick(object sender, EventArgs e)
{
timer1.Stop();
ReportDocument rpt = new ReportDocument();
string path = Application.StartupPath + @"\Report.rpt";
rpt.Load(path);
... etc
}