Remove/change "?s=" from search button

Hello,
In source code of every page I found something like this:
<a href=”?s=” rel=”nofollow” data-avia-search-tooltip=”
<form action="http://kusnachtpractice.com/&quot; id="searchform" method="get" class="">
<div>
<input type="submit" value="" id="searchsubmit" class="button avia-font-entypo-fontello" />
<input type="text" id="s" name="s" value="" placeholder=’Search’ />
</div>
<input type=’hidden’ name=’lang’ value=’en’ /></form>” aria-hidden=’true’ data-av_icon=’’ data-av_iconfont=’entypo-fontello’><span class=”avia_hidden_link_text”>Search</span>

SEO campany advise is to remove this “?s=” because it gives a 302 redirection.
Thank You
Regards
Piotr