The Community of Christ announced on May 5 that the President of the Quorum of 12, James Slauter, will resign effective August 1, 2011, in order to be in better position to help his family deal with a serious illness of his 5-year-old grandson. Apostle Slauter will be ordained to the office of an Evangelist (Patriarch in LDS terms), which is not in the administrative line.
Because the CofChrist next meets in a conference which could sustain a replacement Apostle in the spring of 2013, the Quorum of Twelve will be short-handed until that time. This is not unprecedented in the CofChrist; as recently as the mid-20th Century it was actually rare to have a full quorum of Twelve.
The remaining members of the Twelve will meet, probably as soon as their schedules can be meshed, to elect a new quorum president from among themselves. Unlike in the LDS, the Quorum Presidency is NOT chosen by seniority. Currently the only remaining Quorum officer is the Quorum Secretary, Apostle Linda Booth. Since the Quorum officers tend to be more focused on HQ-related issues than their colleagues, who are more field-oriented, Apostle Booth would be considered a strong possibility to be elected to minimize disruption, IMO.