Ellen borrowed money from RBC. The promissory note she signed set out the interest rates and terms of payment. Ellen was unable to make those payments a year later and re-negotiated the terms with RBC. She signed a new note with the new interest rate and terms of payment. After six months she was unable to make those payment and RBC filed suit against her under the original promissory note. She raised the defence that the original agreement had been discharged by the execution of the second note and could not be sued upon. Is she right? Why or why not?