Some things may require filing an amendment with the Secretary of State.

Here is what the SEC chairman Jay Clayton stated recently in Senate testimony:"I expect the Commission to consider staff recommendations to amend the accredited investor definition in the near future, including whether the definition should include non-wealth-based ways for individuals to qualify, and more broadly, whether the limitations on who can invest in certain exempt offerings provide an appropriate level of investor protection or pose an undue obstacle to capital formation or investor access to investment opportunities."

@Michael Acheampong offer is contingent, so you should be able to make an amendment.

Philadelphia City Council passed a new lead bill which amends the current law regarding lead in rental properties in Philadelphia and is effective October 1, 2020.

You may be able to find the forms for free in your library or a realtor may be willing to send you the form and the amendment.

Do I take it over with a lease amendment that replaces the property manager's name with our name on the existing lease?

If you are coming to the end of the time limit, then you should amend the contract to give yourself more time to complete the inspections. 

I think they could amend the original agreement to say agent sell X shares equally 60% ownership to investors A, B and C.

If you didn't report the income from the past years but you think that you should have, I would reach out to a tax professional to exam your previous tax returns and see if amendments are needed.

This can be handled by a lease amendment.