If you have chosen an incorrect certificate type and entered some details you should use the copy facility to copy into the correct certificate type as detailed in this help article
As long as the original report has not been issued you can contact support@electraform.co.uk and request that we delete it.
If you have not entered details into the incorrect report you may wish to consiider archiving it and keeping for future use. Alternatively you can ask support@electraform.co.uk to delete it which will restore the credit used to create it.