BlueNRG-2 :- Unable to erase a particular flash memory area .

[ARoul.1]

I am trying to erase a particular flash memory area on BlueNRG-2.

here i am getting two library function

1. void FLASH_ErasePage(uint16_t PageNumber) :- where i can erase a page .
2. void FLASH_EraseAllFlash(void):- where i can erase all the flash area.

But how can i erase a random memory boundary.

kindly help me out.