The title of your question is different from the detailed text. Are you proposing to break your S election and revert to a C Corp? Or are you proposing an acquisition of an S corp by a C? Breaking an S election usually doesn't have any tax consequence other setting up a bar to re-electing S status in the future. Without more information I can't really say more. Your tax advisor (CPA or tax attorney) should be able to help you.
If this is an asset acquisition of the S-Corp's assets by the C-Corp then it may creat taxable transactions for the S-Corp if the assets are "sold" at a profit. If it's simply a conversion from S status to C status then there should be no tax implications. Touchbase with your tax adviser to review what you're proposing and normally these types of transitions can be designed so as no to have tax consequences.
More information is need to understand the true focus of your question. However, the conversion of an S corporation into a C corporation would have a profound effect upon the manner in which that corporation is taxed. A subchapter S corporation is essentially a corporation that has elected to be taxed in a manner similar to a partnership. Such an election avoids the double taxation of income at both the corporate level and the individual shareholder level. An S Corporation effectively pays no income tax at the federal level. The shareholders are taxed individually on the corporate income even if that income has not been distributed from the corporation. A C Corporation pays tax at the corporate level on the corporation's net income. The share holders are taxed as dividends on the income or profits actually distributed to the shareholders. You must understand these basic rules to avoid or minimize tax on the income earned. You can reduce the corpoate level tax of a C corporation by paying wages to a shareholder also working for the corporation. But, you must also withhold payroll taxes on the amounts distributed for those distributions to be recognized as income. If you are unaware of this differance and simply make distributions from the C corporation to you that do not qualify for wages, the combined federal and state tax at the corporate and individual level on those distributions can be as high as 79 cents on the dollar. Be certain to review whatever you are seeking to accompolish to be certain that you truly understand the consequences of the proposed transaction.