A conservation easement must last forever, or as the Internal Revenue Code states, a restriction for a conservation purpose must be in perpetuity. However, forever is a long time and many things can change, such as the nature of the property, character of surrounding properties, and the desires of different landowners. A conservation easement can be written to take into account some of these changes, but many events and circumstances are unforeseeable. For example, would someone a hundred years ago be able to draft a conservation easement that would address cell phone towers?

Amending, transferring, and terminating conservation easements is usually disfavored, but there is one legal doctrine that has been generally accepted by courts as a way to modify or terminate a conservation easement: the doctrine of cy-pres. Cy-pres is the idea that if subsequent circumstances frustrate the conservation purpose to the point that it would be impossible or impractical to continue using the property for that purpose the court can amend or terminate the easement. However, the court will try and ensure that the property, money from sale of the property, or any resulting benefit will be used in a manner that is as close as possible to the original conservation purpose.

Extinguishment.  If a subsequent unexpected change in the conditions surrounding the property make the continued use of the property for conservation purposes impossible or impractical, the conservation purpose can nonetheless be treated as protected in perpetuity if the restrictions are extinguished by judicial proceeding and all of the donee's proceeds from the sale or exchange of the property is used by the donee organization in a manner consistent with the conservation purposes of the original contribution.

Transfer by Donee.  Generally, a qualified organization that obtains a conservation easement may not transfer the property. However, when an unexpected change in the conditions surrounding the donated property makes it impossible or impractical to continue using the property for the stated conservation purpose the property can be sold or exchanged. A donee organization may also seek to sell or exchange the property to another qualified organization if it must close its doors.

A donee may only transfer the property if it requires that the conservation purposes, which the contribution was originally intended to advance, continue to be carried out. The subsequent transfer must also be to a donee that is a qualified organization at the time of the transfer. Furthermore, the proceeds from the transaction must be used by the donee organization in a manner consistent with the conservation purposes of the original contribution.
 
Amendment. Conservation easements may be amended, but each state has slightly different rules that will govern the amendment. In general, under the federal Uniform Conservation Easement Act, a conservation easement can be amended like any other easement- with the consent of both the landowner and easement holder. Routine amendments, such as to fix clerical errors, that do not substantially impact the conservation purpose are also generally permitted. However, it is important to remember that Congress laid out a strong policy that disfavors amending easements to ensure that the charitable purposes are maintained. Thus, the doctrine of cy-pres will be used as a guidepost in the amendment process, and an amendment will be permitted so long as it does not have a detrimental impact on the conservation purpose or is needed to amend an impossible easements to be as close the original conservation purpose as possible.