By default all employees have the same number of allowed days but in certain situations you may need to give a higher number of allowance to certain employees (e.g. company CEO).
All you need to do is go to Settings > TIME OFF > Individual allowances.
There you will see a table of all your employees & their policies.
Simply find the employee you need & change the number of days available for specific policy. Then click "Save changes" at the bottom.
Note: this allowance will be same for all future periods as well. E.g. if you give 25 days vacation allowance, next year it will be the same 25 days.