The Supreme Court's statement about pornography -- "I can't define it but I know it when I see it" -- fits the doctrine of undue influence. Every person making a will is influenced by others, but only excessive influence invalidates a will or bequest. Undue influence occurs when a testator’s free will is usurped by the will of another, according to the American Bar Association. Courts hearing undue influence charges look at the relationship between the parties, the susceptibility of the testator and the opportunity of the named heir to exert pressure.
Gather evidence of undue influence. Review letters, contracts and other documents between the testator and the named heir. Talk to will witnesses as well as neighbors and family members. Look for proof of a confidential relationship between the testator and the named heir, a growing dependence on the part of the testator and pressure exerted by the named heir to change the will.
Hire a will contest attorney. Alternatively, educate yourself about will contest procedures in your jurisdiction. Ask timing and procedural questions at the court clerk's office. Get copies of probate statutes and local rules specifying will contest procedures. Take full advantage of self-help services offered by the court. Determine standing issues — in many states, only family members can object to a will. Mark down the deadline for filing an objection to the will, and familiarize yourself with format and procedural requirements.
Draft and file an objection to the will in the format required in your state. Include a description of your relationship to the will. Specify that the grounds are undue influence. Include a summary of your evidence if required by your jurisdiction. The court will notify all interested parties and name a hearing date.
Prepare for the trial on the will contest issues. You will be required to present affirmative evidence of undue influence.
Bring your evidence and witnesses to the court on the day and time assigned for hearing. Convince the court that the testator was not acting freely when she made the will. Support each point with written evidence or testimony from witnesses.