Investing 102

[booah]

I have a question.
I have shares in an energy company CoP and they are about to reposition the company splitting the refineries and downstream side of the company to become Phillips 66. When the split happens they are giving every shareholder 1 Phillips 66 share for every 2 CoP shares they own. If you don't have the brokerage set up to accept the shares they will automatically sell the new Phillips 66 shares and give you the cash. You get hit with capital gains for the income tax year.
My question is: Do companies such as this lose share value right off the bat and then gain or is it just a guess?
I need to know what to do within a week and get accts set up keep, the Phillips shares or take the money and run, which is the default easy option.