To change a time for your party, you will need to edit a party pass.
1) Go to your Host Dashboard.
2) Click on "Passes".
3) Select the party that you want to edit, by clicking on "Edit".
4) Then you will be able to adjust start and end time for your party.
Remember, it's your responsibility to let know the guests who bought the party pass that you're changing time for particular party date. They will be able to request a refund if the new time of a party isn't suitable for them.