Section 10-5.3. Contract to appoint; power not presently exercisable

(a)  The  donee  of  a  power  of  appointment  which is not presently
  exercisable, or of a postponed power which has not  become  exercisable,
  cannot  contract  to  make  an appointment; except that this prohibition
  shall not apply if the donor and donee  are  the  same  person.  Such  a
  prohibited  contract,  if  made,  cannot  be  the basis of an action for
  specific performance or damages, but the promisee can obtain restitution
  of the value given by him for the promise unless the donee has exercised
  the power pursuant to the contract.
    (b) The provisions of this section shall not abridge  the  ability  of
  the  donee  of a power of appointment which is not presently exercisable
  to release his power pursuant to 10-9.2 or  to  make  the  power,  after
  release,  an  imperative  power,  except that where the donor designated
  persons or a class to take in default of the  donee's  exercise  of  the
  power,  a  release  with  respect  to  appointive property must serve to
  benefit all those so designated as provided by the donor.