ESOP RESTATED as Profit Sharing/401(k)?

Can a ESOP consisting only of cash (employer bought back stock) be "restated" as a profit sharing plan or a 401(k) plan? 

If yes, will the continuing plan be grandfathered and not subject to the automatic enrollment rules? 

Thank you, 

I think yes, it would actually have to convert to PS as it would no longer satisfy requirements of an ESOP. However, if there was never a 401(k) provision and that component plan is new I believe it will be subject to auto enrollment rules.

@susieQ it is fairly common for the ESOP document to be structured so that the plan was a profit sharing plan and the ESOP was a stock bonus component embedded in that plan.  The plan may already be a profit sharing plan and there is no need for a restatement.

If the plan is a profit sharing (either by default or by restating the ESOP into a profit sharing plan) be mindful that the plan must follow all of the rules regarding the investment of the assets.

@CuseFan is correct that adding a 401(k) feature to the plan now (post the SECURE 2.0 mandate) is subject to auto enrollment rules.