In Calamari Leave module you can apply for upcoming absences.
However - it may happen that you have to update your calendar with an absence that has already took place some time ago.
In order to request a time off in the past you have to go to Apply tab, and process a regular request indicating certain dates from the past.
Depending on your organization's policy the request may be processed normally, or it can be blocked from further processing with information that you're breaking the company's policy because it's not allowed to request absences in the past:
This means that general rules in your organization don't allow updating historical data. You have to contact the Calamari administrator in your organization and highlight your case - they should be able to allow you to update the historical requests or find another solution for this particular situation.