To display future reservations use Advanced Search.

For example now is April/2018, to display only May/2018 reservations define the search listed in the Search Condition box (1).

Use CURRENT_DATE (1) and define manually the search condition.

This search regardless of the execution date will always use and compare today's date (defined by CURRENT_DATE) with RESERVEDON. This search will only display records where:
Reserved On is greater than today's date + 10 AND Reserved On is less than today's date + 21

You can save (2) the search definition and it will be listed in the View (3) box.

Question: