**Input**: A qubit in state $\ket{\psi} = \alpha \ket{0} + \beta \ket{1}$.

**Goal**: Change the state of the qubit as follows:

- If the qubit is in state $\ket{0}$, change its state to $\ket{+} = \frac{1}{\sqrt{2}} \big(\ket{0} + \ket{1}\big)$.
- If the qubit is in state $\ket{1}$, change its state to $\ket{-} = \frac{1}{\sqrt{2}} \big(\ket{0} - \ket{1}\big)$.
- If the qubit is in superposition, change its state according to the effect on basis vectors.
