As an heir or recipient listed in a loved ones' will, the process of being granted the assets directed to you is not always smooth - especially if your name is "whited out" by someone other than the owner of the will, such as a their spouse or your stepparent. The proper procedure to contest this action would be to petition the court with jurisdiction over the estate to contest the validity of the will.
A will with actual "white out" on it might be difficult to hold up in court, but if nobody has stepped forward with any issues regarding the "whiting out" of a certain heir, an opportunity to contest the action can be limited depending on how much time has passed. If the will appears to be invalid based on informal "corrections" made to the will, the court may throw it out and instead use "intestate succession" laws to distribute the funds and assets of the deceased individual, which is the process undertaken when no will exists at all.
In most cases, without a will, the court would award all funds and assets to the spouse of the deceased, but it is up to you to contest the will and demonstrate that the "true wishes" of the will's owner was to leave the property to you. If you do not take action, the estate will be formally probated, which takes approximately a year or two and you will be unable to contest the process unless you can prove fraud. Proving fraud may be possible if whoever amended the will did so with actual white out, but the best way to ensure that a will is executed properly is for the owner to periodically update it in order to prevent confusion regarding any changes made that may prompt a challenge to its validity upon death.