Below is an instruction that describes a task. Write a response that appropriately completes the request.

### Instruction:
What was the state (class) where the new successor was formally installed on May 11, 1966?

### Inputs:
table_name: table, columns: ['State (class)', 'Vacator', 'Reason for change', 'Successor', 'Date of successors formal installation']

### Response:
SELECT State (class) FROM table WHERE Date of successors formal installation = May 11, 1966