Verify your status as an interested person. An interested person is usually someone who is entitled to receive under the will, but could also be someone who has a statutory right to part of the estate, such as a spouse, or someone who would be entitled to property under the laws of intestacy if the will were invalidated. Simply being related to the decedent does not necessarily make you an interested party to the estate.
Identify a ground for challenging the will. You can't simply challenge a will because you don't like what it says. Instead, you must raise one of several recognized reasons for invalidating all or part of a will. Generally these involve the testator's mental state at the time of making the will, the failure to follow the appropriate formalities in executing the will or the fraudulent or undue influence of a third party on the contents of the will.
File a bill in equity either challenging the will or establishing a new will for probate. Under Virginia Code section 64-1.88, an interested person can file a challenge to the will. According to Virginia Estate Law, this challenge can be filed within six months of the order of probate if issued by the probate clerk or one year if issued by a judge. The bill should state why you are an interested person and your reason for challenging the probated will.
Attend a hearing. To prevent delay in administering the estate, the probate court will most likely quickly set your challenge for hearing, according to the Virginia Estate Law website.