state (class)             vacator                                 reason for change                      successor date of successors formal installation
0    maryland (3)              vacant  sen thomas h hicks died during previous congress             john creswell (uu)                         march 9 , 1865
1  new jersey (2)              vacant              presented credentials as sen - elect            john p stockton (d)                        march 15 , 1865
2   tennessee (2)              vacant              tennessee re - admitted to the union           joseph s fowler (uu)                         july 24 , 1866
3   tennessee (1)              vacant              tennessee re - admitted to the union          david t patterson (u)                         july 28 , 1866
4     vermont (3)  jacob collamer (r)                            died november 9 , 1865              luke p poland (r)                     november 21 , 1865
5     vermont (1)    solomon foot (r)                              died march 28 , 1866           george f edmunds (r)                         april 3 , 1866
6  new jersey (1)  william wright (d)                            died november 1 , 1866  frederick t frelinghuysen (r)                     november 12 , 1866
7    nebraska (1)            new seat     nebraska admitted to the union march 1 , 1867              thomas tipton (r)                         march 1 , 1867

Table as JSON:
{"state (class)":{"0":"maryland (3)","1":"new jersey (2)","2":"tennessee (2)","3":"tennessee (1)","4":"vermont (3)","5":"vermont (1)","6":"new jersey (1)","7":"nebraska (1)"},"vacator":{"0":"vacant","1":"vacant","2":"vacant","3":"vacant","4":"jacob collamer (r)","5":"solomon foot (r)","6":"william wright (d)","7":"new seat"},"reason for change":{"0":"sen thomas h hicks died during previous congress","1":"presented credentials as sen - elect","2":"tennessee re - admitted to the union","3":"tennessee re - admitted to the union","4":"died november 9 , 1865","5":"died march 28 , 1866","6":"died november 1 , 1866","7":"nebraska admitted to the union march 1 , 1867"},"successor":{"0":"john creswell (uu)","1":"john p stockton (d)","2":"joseph s fowler (uu)","3":"david t patterson (u)","4":"luke p poland (r)","5":"george f edmunds (r)","6":"frederick t frelinghuysen (r)","7":"thomas tipton (r)"},"date of successors formal installation":{"0":"march 9 , 1865","1":"march 15 , 1865","2":"july 24 , 1866","3":"july 28 , 1866","4":"november 21 , 1865","5":"april 3 , 1866","6":"november 12 , 1866","7":"march 1 , 1867"}}