How do I cancel the resource for a private appointment I set up?

I am new to Outlook. We have now been able to schedule meetings and
conference rooms using the meeting invite and resources. I scheduled a
meeting with a conference room, marked the meeting as private and labelled
the time as "FREE". I wanted to change the meeting to NOT be private and
book time as "BUSY". I cancelled the meeting and created a new meeting with
the new specifications. Now, my calendar only has the new meeting but the
conference room calendar still has the "Private Appointment" listed as well
as the new meeting. How can I delete the "Private Appointment" to clean up
the conference room calendar?