You can create promo codes that are only usable within a certain time period. The Start Date and End Date will decide on what dates orders can be placed, not the dates the orders will be placed for

For example, if I create a promo code with a Start Date of January 1 and an End Date of January 5, customers can start placing orders on January 1 for any future date and won't be able to place orders with that promo code beginning January 6. They won't, however, be able to place orders on December 31 for a date that falls within the January 1 - January 5 timeframe. 

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