First, you need to identify which donation form your TeamRaiser event is using. To do so:
  1. Click on Fundraising > TeamRaiser. 
  2. Find the TeamRaiser you want to change in the list and click the Edit button. 
  3. Click on Step 2: Select Fundraising Options. 
  4. The very first field on that page is the donation campaign and donation form that you are using. Take note of the name of the form from that field. 
Now that you know which form you are using, you'll unpublish that form, edit it to remove the sustaining gift option, and then publish it again. To do so:
  1. Click on Fundraising > Donation Management.
  2. Click Unpublish next to the form you are using.
  3. Click Edit next to the form you just unpublished. 
  4. Click on Step 3: Design Donor Screens, and then click Edit next to Donation Form. 
  5. Once you're on that screen you'll see two boxes at the top. Select "Flexible Sustainer Donation Level" from the right box and click the Remove button. Then in the left box select "Standard Donation Level" and then the Add button. Then make sure "Standard Donation Level" is selected within the right box and click Save Order and Edit Selected, just below that box. 
  6. In the Edit Data Element section, make sure the "Yes, allow optional recurring behavior" check box is not selected. 
  7. Click Finish. 
  8. Click on Step 8: Publish, and publish the form immediately.