When I create a dashboard prompt on a date value, there are several options available for User Input.
If I select "Choice List" here, then I am given another option to "Enable users to select multiple values".
However, if I select "Calendar" for User Input, then I do not have the option to "Enable users to select multiple values".
Is there a way to do this with the "Calendar" option?
Not really, the calendar view is really simple and just show a calendar without other options where you select 1 date. If you want to have the other options you need to stay on choice list or one of the "standard" types.