We have all been there. You have a game planned and then something comes up that drastically changes your schedule in an instant. This is for those situations, when you absolutely NEED to cancel or reschedule an upcoming game.
The most important thing to do if you need to cancel or reschedule a game is to notify your players. Give them as much warning as you can, and try to find a new time that will work for everyone. Send a message through the site, post in whatever chat service your group uses for online games, or send out an email if you must. Whether you need to reschedule the session or outright cancel, follow the steps below.
Go To Your GM Dashboard Or "Adventures" Menu
Clicking on "GM Dashboard" will take you to a set of options where you will click on "Adventures". You can also click "Adventures" straight from the home page's drop-down menu. Either way, you'll be brought to a page that shows all the adventures you currently have active.
Find The Adventure That Has Session You Need To Cancel, And Hit "Edit Adventure"
In the "Adventures" section, you can further filter into campaigns and one-shots to help you sort through. Once you've found the session that needs to be canceled or rescheduled, hit the blue "Edit Adventure" button.
Find The "Schedule" Slide And Hit The Pencil Icon
The schedule will show you all upcoming games of a certain adventure. Find the date you wish to cancel and click on the little blue pencil icon. This will open up a menu that allows you to reschedule or cancel the session in question.
If you're simply cancelling, hit the red "Cancel Session" button. With that, the session will be no more. If you want to reschedule instead, you can use the date and time fields to pick a new session day. Hit the blue "Reschedule" button to confirm the choice.
One last thing to note is that StartPlaying charges players for a session about one hour after the listed start time. Unnecessary charges can be avoided if a session is cancelled with enough notice. If a charge does end up going through, players can settle the issue with the DM (such as simply having the charge count towards the next session instead) or reach out to support for help with a refund.