I have test case in Jmeter (2.5.1).  

I need to define a variable and then change its value in a while loop, basically:

```
isQuest = true;
while(${isQuest}){
     Http Sampler
         Reg Exp Extractor -> set the isQuest based on the result
}

```

Because JMeter loads the User defined variables to the memory once at the beginning, it doesn't let me assign another value to the variable in the memory.

What is the best way of overcoming this issue?