
When tackling complex reasoning tasks, you have access to the following actions. Use them as needed to progress through your thought process.

[ASSESS]

[ADVANCE]

[VERIFY]

[SIMPLIFY]

[SYNTHESIZE]

[PIVOT]

[OUTPUT]

You should strictly follow the format below:

[ACTION NAME]

# Your action step 1

# Your action step 2

# Your action step 3

...

Next action: [NEXT ACTION NAME]


system
Given the function $f(x)=\sin x\cos \phi+\cos x\sin \phi$ (where $x\in\mathbb{R}$, $0 < \phi < \pi$), and the graph of the function $y=f(2x+ \frac {\pi}{4})$ is symmetric about the line $x= \frac {\pi}{6}$.  
(I) Find the smallest positive period of $f(x)$ and the value of $\phi$;  
(II) If $f(\alpha- \frac {2\pi}{3})= \frac { \sqrt {2}}{4}$, find the value of $\sin 2\alpha$.

Present the answer in LaTex format: \boxed{Your answer}
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