In order to select multiple blocked dates from the Blocked Date list and remove the selected ones, go to the Calendar -> Calendar Toolbox and select View Blocked Date List.
On the Blocked Dates Dashboard, select the multiple blocked dates you wish to remove. Then, click on the three dots on the top right of the list to Remove.
Note: If you wish to remove one blocked date, click on the three dots of the entry of your choice to Remove.
