Retroactive Amendment-401k plan

[Guest meggie]

If a plan sponsor should decide to amend the plan to allow a person into the plan that was erroneously included earlier than he should have (i.e. should have waited 6months but entered immediatelyin 2001), can the retroactive amendment be worded ---"immediate entry effective 1/1/2001, and 6 months wait effective 1/1/02", with an adoption date of 2003? In other words, retain the current eligibility requirements but adjust for only one year when the error occurred.

Thanks.