To present any new evidence, you would have to go through the review process at the Board. The process is described in the following Interpretation Guideline: https://tribunalsontario.ca/documents/ltb/Interpretation%20Guidelines/08%20-%20Review%20of%20an%20Order.html

The form you require is the Request to Review an Order. The form and instructions are available here: https://tribunalsontario.ca/ltb/forms/#landlord-forms

The new evidence issue is mentioned in the interpretation guideline, and is described as a serious error, as follows: “New evidence which was unavailable at the time of the hearing and which is potentially determinative of one or more central issues in dispute…”