A:AnswerJen,
You have to loosen both sides and possibly loosen the two nuts at the bottom of the tilt assembly. Contact us directly using the support button on our website if you have any additional questions, thanks.
A:AnswerCade,
The maximum VESA pattern (bolt pattern) our M300 can support is 400x400. Your TV will not work on this mount but all of our dual studs mounts will be able to support your Vizio. Contact us directly using the support button on our site if you have any other questions, thanks.