Every Pin can be sent right away with "Publish now" or scheduled for a specific date and time. Scheduled Pins show up on the Weekly Plan calendar, where you can drag them to a new day or edit the time from the Pin's details. Smart Schedule can also pick good times for you automatically.
What you can try
From a Pin's details, choose "Publish now" to send it immediately, or "Schedule" to set a date and time.
Find scheduled Pins on the Weekly Plan calendar and drag them to reschedule.
Open a Pin's details to edit its scheduled time directly.
Use Smart Schedule to have times picked for you automatically.
Turn on "Keep this time" for a Pin if you don't want automatic rebalancing to move it.
A scheduled Pin still needs a usable image and a Pinterest board. Copy and alt text can be completed later.
If a scheduled Pin didn't go out, contact support.