Just enter both w2's normally.

If as you say there is an overpayment of social security it will automatically show on the tax return as additional money withheld for income taxes. End of problem.

I would question the mentality of the new owners accountants having them start a new company rather than just buying the corporate stock in the previous corporation ( If we are talking corporations ) because that new company had to match the social security withheld which they would not have to do if the corporation was just operating under the old corporate charter. And then there is federal and state unemployment tax that they had to pay when the previous company had already reached the limit. And that is why they pay these people the big bucks?