I have a scenario, where I need to clear the start date and end date based on the checkbox.
When I am unchecking the checkbox, the start and end date should be cleared. Currently we are maintaining it based on conditional formatting to make it red when no checkbox is checked and date is present.
Good question. The answer is you cannot change an editable line item using a checkbox. BUT, you can create another line item that equals the date if the checkbox is unchecked and BLANK() if the Boolean is checked. Your only other options would be to create a line item that is empty and run an import action to clear your dates. Not ideal but it would work too.
Believe you anyways want to control such actions through dashboard therefore as Jared also pointed out to create actions to achieve the result, you have to create action (/button) on dashboard and click that button in place to checkbox to achieve the desired output.