law: Indian Trusts Act, 1882 
  78. Revocation of trust 
  A trust created by will may be revoked at the pleasure of the
  
  testator.
  A trust otherwise created can be revoked only- 
  (a) where all the beneficiaries are competent to contract-by
  
  their consent;
  (b) where the trust has been declared by a non-testamentary
  
  instrument or by word of mouth-in exercise of a power of revocation expressly
  
  reserved to the author of the trust; or
  (c) where the trust is for the payment of the debts of the
  
  author of the trust, and has not been communicated to the creditors at the
  
  pleasure of the author of the trust.
  Illustration 
  A conveys property to B in trust to sell the same and pay out of
  
  the proceeds the claims of A's creditors. A reserves no power of revocation. If
  
  no communication has been made to the creditors, A may revoke the trust. But if
  
  the creditors are parties to the arrangement, the trust cannot be revoked
  
  without their consent.