Absolutely! One of the best parts about creating an event through Splash is that all of the information appearing on the event page is customizable.
If something is TBD, just check this option during event creation or in the Settings tab and edit it later.
1. Click on the Settings tab in your event page's toolbar.
2. Under Date & Time and Venue, you'll have the option to mark these two elements as TBD.
Heads up! This will also appear by default on your Splash page and in confirmation emails.