How can I free up a used appointment slot?

I do have one problem that I am not sure how to resolve. I have a had a few people sign up for a time that they no longer can make. I would like to free that time up so someone else can sign up. How do I go about doing that?

Hi,

I would advise removing that particular time and re-add it. That serve as a new item to the widget options.

Thank you!

I tried deleting the time and saving the form and then re-adding the time but it still shows the time as taken.

It seems to me that you would like to free-up time in the appointment widget and can't. 

To do this you have to delete the submission itself and that will free up the time on your form.

Example: