To do that:
- Go to the On-Sale tab of the Scheduled Program.
- Click the On-Sale tab
- Click on the circular chevron next to Online Sales and click Edit
- In the On-sale Period Begins drop down choose Specific Date
- Add the specific date information to the Date Field
- Check the box to Allow members to buy tickets in advance
- Add the specific membership program and levels that are allowed to buy these tickets in advance.