Data: New Jersey (2) VACATOR Vacant; New Jersey (2) SUCCESSOR John P. Stockton (D); Vacant REASON_FOR_CHANGE Presented credentials as Sen-elect; John P. Stockton (D) DATE_OF_SUCCESSORS_FORMAL_INSTALLATION March 15, 1865

What would a sentence about this data be like?
The reason for change in staff for the installation on March 15, 1865 was "presented credentials as sen - elect."