Replace string of last two matchings
<p>How can I replace the last two matched string</p>

<p><code>string s= "{\"test\":\"value\"}";</code></p>

<p>From this string "s" I need to remove the double quotes of the value.</p>

<p>But I need generic, like the value may be any string in feature.</p>

<p>I need this to be done in <code>C#</code>.</p>
