Problem in changing delimit date of a position

Hello All,

i have delimited a position (S 5******) to 01.08.2014 in PPOME. Later i have realized that the year should be 2015. i had tried to changed the delimit date from 01.08.2014 to 01.08.2015 but i am getting a pop up such as, "Select the date between 05.02.2005 and 01.08.2014". Could you please help me changing this date to 01.08.2015.