Write/Read to-from flash

[kingGrey]

I am using p33FJ1128GP708

It is my understanding that when I declare Const Vraiable, the pic write this data at an offset in Flash. What I would like to to do it to be able to define variables at constants with default declaration. for eg

Const firstStr as String[6] = "OLDER"

Then if I needed to modify this later on, I could use

Flash_Read(address,buffer, size)
Modify this buffer and use
Flash_write(....)

But my question are
- how do I access firstStr by using Flash_Read routine
- after maybe changing the data of firstStr to "Hello", how
would I erase and write this string back to flash memory

any help is appreciated