This policy applies to Voting Members, but not Associate Members. The policy is in the Republican Party of Virginia Bylaws and the full version can be found here.
SECTION D. Absences
A member of an Official Committee other than an ex-officio member automatically loses his committee position if he is absent three (3) consecutive meetings without representation by a person holding a proxy; provided, however, that a State Central Committee member automatically loses and is deemed to have resigned his Committee position if he fails to attend in person at least fifty (50) percent of the regular meetings in any calendar year. A vacancy created by such resignation shall be filled in accordance with the State Party Plan. In the case of an ex-officio member with voting privileges, those voting privileges shall be suspended if he is absent three (3) consecutive meetings. Voting privileges for an ex-officio member that has been suspended may be restored by a two-thirds (2/3) vote of the other members of the committee.