However, I don't think I was trying to modify the contract, that is the same version of the lease I have sent them at least three times before the end of the lease. And I know he can sue me if I deduct the deposit as well as I can deduct the deposit because of the damage to the house caused by them if he refuses to sign the addendum. 
But I have to admit that I don't have any legal backgrounds/knowledge and what I have written here are based on my own thoughts, that is why I am here and try to learn. Anyway, I do apprecitate your time, I did learn something from you today. 
I appreciate your time and informative replies.
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                    What you should have done is threatening eviction
                     -lexm5- 
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                        09/22/2014 postreply
                                                12:19:17
                    
                    
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                    Thanks.
                     -sleepyfox- 
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                        09/22/2014 postreply
                                                12:35:27
                    
                    
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                    New lease doesn't have to be post-date
                     -lexm5- 
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                        09/22/2014 postreply
                                                12:44:06
                    
                    
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                    You are right.
                     -sleepyfox- 
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                        09/22/2014 postreply
                                                13:09:54