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

### Instruction:
What episode was the last appearance of the character, rikki sandoval?

### Inputs:
table_name: table, columns: ['Character', 'Portrayed by', 'Relationship', 'First appearance', 'Last appearance']

### Response:
SELECT Last appearance FROM table WHERE Character = Rikki Sandoval