This can be done either in the Receipt Manager or by disabling the associated autoresponder.

To configure the store to not send receipts (allowing an autoresponder to be sent out but without a receipt):
  1. Go to "Setup" > "Receipt Manager"
  2. Find and "Edit" the desired receipt
  3. Go to step 3, "Select Applications"
  4. Click on "Configure" next to the desired application.
  5. Select the specific object (donation form, eCommerce store, etc.) on the left to add or the right to remove.
  6. Click "Add" or "Remove" as desired.
  7. Click "Finish" or "Save"
To disable the autoresponder for the store:
  1. In the desired application find and edit the specific object (donation form, eCommerce store, etc.).
  2. Go to the step where you can configure the autoresponders.
  3. Click "Disable" next to desired autoresponder.
If you do not have Receipt Manager turned on, contact support.