They replaced phi with 2pi*vt, then factored out the common factor 2pi.
[tex]y = A\sin\left(\phi - \frac{2\pi}{\lambda}x\right)\\\\y = A\sin\left(2\pi vt - \frac{2\pi}{\lambda}x\right)\\\\y = A\sin\left(2\pi vt - 2\pi\frac{x}{\lambda}\right)\\\\y = A\sin\left(2\pi\left(vt - \frac{x}{\lambda}\right)\right)\\\\[/tex]
Hopefully that clears things up. If not, then let me know.
