[ns] change transmission range

[jeni martin]

hi all,
 
i had a question, can we change the transmission range during simulation? i don't mean in .tcl file, i mean in .cc file, i want a node in a condition, increase it's range, like :
 
if(fwd_state) { 
 
     increase the transmission range;
 
}
 
how can do it in code??