Hello @treettfs,
Thanks for your inquiry,
For time and date field we don’t have such an option.
You can try to manage this functionality like this: you can write the available dates and times in a database table.
Then you can add a a select field and choose the option from database, connect that table with the select field.
Then you should enter the form > settings > MySQL mapping and add a query there to delete a row in the table when the certain option will be selected. This way the option will be automatically removed from the select field.
Hope this will work for you.
As an alternative, you can also try this option, add a text input field, mark the option Allow only unique values (under Advanced section) and add a regular expression which will define the date and time format you accept.
If you’ll have any difficulties, please let us know.