google: Va. Code Ann. § 55-222
This section shall not apply when, by special agreement, no notice is to be given; nor shall notice be necessary from or to a tenant whose term is to end at a certain time.
Also google:
Supreme Court of Virginia. Joseph B. SWEENEY v. WEST GROUP, INC. - See more at: http://caselaw.findlaw.com/va-supreme-court/1060296.html#sthash.Qc0haYLy.dpuf