Hi,
I am 50 years old and was laid-off more than a year ago. I had the enhanced pension distribution where lumpsum was transferred to an IRA account. This company discontinued their pension plan about 3 years ago. If this same company wants to rehire me is there a waiting period before I can be hired by them? Can I work as a contractor, can I work as permanent employee at the same company? Is there anything in the IRS rule that says the same company cannot hire me back?
I appreciate your answer.

You should either contact the employer or review the severance agreement that you signed if any to find out if there is any restriction on your return. The IRS does not regulate rehiring of employees.