It is important for you, as a person organizing an educational seminar, to get confirmations from the important stakeholders, before the day of the actual seminar.
One group of stakeholders you need to get confirmation from is that of the facilitators. These are the resource people meant to address the attendees of the seminar on the issues that the seminar is meant to deal with.
Another group of stakeholders you need to get confirmation from is that of the targeted attendees.
Yet another group of stakeholders you need to get confirmation from is that of the owners of the facility where the seminar is meant to take place.
You can obtain these confirmations through the phone: by calling the people in question, and asking them to confirm availability to facilitate the seminar, availability to attend the seminar or availability of the facilities for the seminar. You could also email the people in question, and ask them to confirm via email. To make this possible, you may need to, say, go to the Gmail.com sign up page, and create a Gmail email account, for use in obtaining the confirmations. This is especially the case if you are not very keen on using your principal email account for this particular purpose.