How to Change section attribute in ELF file

[Minchu Mo <morris_minchu () iwon com>]

My program try to modified one of its sections (.plt) 
loaded into the memory.  But it  got a SIGSEGV 
signal.

The .plt section marked READONLY CODE when I 
used objdump -h myprogram, I am wondering 
whether this readonly attribute can be changed or 
not? I have tried editing it in several places in the file 
but haven't success yet. Anybody done this before?