Sometimes life happens and you can't keep a commitment - we get it. All we ask is that you respect your partner's time by notifying them as soon as you're aware that you cannot make it (especially if it's within the last hour).
To message your partner simply mouse over the session from your dashboard and click the "edit icon". At the bottom of the window that pops up there is a message icon you can click.
Send them a quick apology note explaining that you couldn't make it and then promptly cancel the session.
The quicker you cancel the more likely it will be for them to find a new partner before the sessions begins!