How to cancel a will already made

Sir mere grandfather ne ak vasiyat likhi thi ab vo expire hogaye h vasiyat unhone mere aur mere uncle ke bete ke nam ki h tau ji iss vasiyat ko tudvana chate h vasiyat registered h hamne dakhil kharij ke liye apply bhi kiya hua h but tauji ne varisan ke taur par property ko dakhil kharij ke liye apply kar diya h ab kya kiya jaye tauji kafhi dabang h wo vasiyat ke jo wittness h unko bhi bar bar dhamka rahe h aur hame bhi jan se marne ki dhamki de rahe h ab kya kiya jaye Wo hame bar bar vasiyat todne ke liye dhamka rahe h