title: Solidity: change a the value of a variable in a smart contract already published
body: <p>I'm trying to change the value of a variable in a contract that is in the blockchain. I've deducted its code and is something like this:</p>
  
  <pre><code>pragma solidity ^0.4.8;
  contract Trial {
     address public owner;
     address public person;
     uint initialEther;
     function Trial(address _person) payable {
         owner = msg.sender;
         person = _person;
         initialEther = msg.value;
     }
     modifier only_person() {
         if (msg.sender!=person &amp;&amp; tx.origin!=person) throw;
         _;
     }
  
  
     function() payable {}  
  
     bytes4 public signature = bytes4(sha3("libraryFunction()"));
     bool variableToBeChanged = false;
     function libraryInvocation(address libraryAddress) only_person {
         bool doSomething = libraryAddress.delegatecall(signature);
         if (variableToBeChanged) {
             .....
        }
     }
  }
  </code></pre>
  
  <p>Suppose that I have the right signature of the library function, what I'm trying to do is to change the value of "variableToBeChanged" in order to execute the code inside the if.
  Probably there is a way to create a library with a function with a proper name and inserting assembler code in some way to change the value of the variable. But it's like using an atomic bomb to kill an ant. I'm looking for the simpler way to do this.
  I also know this contract is not safe, I'm trying to understand if this is possible and I want to understand how risky this can be for a contract. </p>