Hello Phillipa!
Thanks for reaching out to us! 🙂 Let me try to help you with that.
The arguments to be passed into $args can only be the ones stated here as a reference >Â https://developer.wordpress.org/reference/functions/wp_insert_post/#parameters
I can see in your code that you might have mismatched the $args variable. Will something like this work for you?
$args = array(
'meta_input' => array(
'PlacesLeft' => '46',
),
);
tribe_update_event (98, $args);
I’m not sure where exactly you are using that code snippet but I suggest you test that out in a test/dev site before doing it so in a live site, because it may have unintended effects.
We also encourage you make a full backup of your site just in case something goes wrong, and you can always revert changes back.
I hope that helps. Let me know if you have other questions.
Best,
Victor