<human>: Give me the gist of the text in a nutshell

This is a fairly common situation where I live. Some people work for a startup and are blessed quickly by many shares of a successful stock. Others, like me, work for a company for several years and accumulate stock along the way. The stock covers the entire range of cost basis, as the stock has risen along the way. Either way, people end up with a decent amount of net worth, but in a highly concentrated stock position. Most times, the employee has zero experience with managing this risk.

There are times where I have lost or regained 40% of my net worth in a year by holding on to this stock. I know others in my situation, ranging from $25K to $2 million+.

So... Where do I start? I have read about equity collars, exchange funds, completion funds, etc. I am concerned with diversifying without losing my shirt to taxes. Who are reputable experts I can consult with in this field? Do big company wealth management services like Merrill Lynch provide the right type of advice, or is there a more specialized type of advisor for this?
<bot>: I have found myself in a potentially disastrous financial situation where the vast majority of my net worth is tied up in one investment. How do I undo this? Who do I talk to first?