law: Indian Trusts Act, 1882 
  47. Trustee cannot delegate 
  A trustee cannot delegate his office or any of his duties either
  
  to a co-trustee or to a stranger, unless (a) the instrument of trust so
  
  provides, or (b) the delegation is in the regular course of business, or (c)
  
  the delegation is necessary, or (d) the beneficiary, being competent to
  
  contract, consents to the delegation.
  Explanation:  The appointment of an attorney or proxy to do
  
  an act merely ministerial and involving no independent discretion is not a
  
  delegation within the meaning of this section.
  Illustrations 
  (a) A bequeaths certain property to B and C on certain trusts to
  
  be executed by them or the survivor of them or the assigns of such survivor. B
  
  dies. C may bequeath the trust-property to D and E upon the trusts of A's will.
  
  
  (b) A is a trustee of certain property with power to sell the
  
  same. A may employ an auctioneer to effect the sale.
  (c) A bequeaths to B fifty houses let at monthly rents in trust
  
  to collect the rents and pay them to C. B may employ a proper person to collect
  
  these rents.