Push Yelp & Opentable down

Have a client that has numerous bad reviews on Yelp & Open Table.

He literally can't put out Positive Reviews quick enough to cancel out the legitimate negative ones by customers. Even if the positive ones stick and are articulate.

You google the company and Yelp/opentable is the very first result. Which is bad all the way around.

How can I push Yelp down?

Based on the little reading I've done, which I would be correct to go with a decent PR Release?
Not something spammy, obviously…..

Push Yelp & Opentable down