An assignee of the morgagee's estate in the land may sue for foreclosure or sale, but to enable a person other than the mortgagee or his personal representative to bring an action for personal payment an assignment of the mortgage debt is necessary (w). In other respects, however, the rules as to the persons who are entitled to sue for foreclosure or sale will apply to an action on the covenant. If there are two or more mortgagees, they must both or all be parties to the action as plaintiffs or defendants; if a mortgagee dies entitled to a mortgage his personal representative must be a party, unless the mortgage was vested in the deceased mortgagee and another or others jointly as trustees or otherwise (x).

Even if the heirs of the mortgagee are named in the covenant for payment, the personal representatives will not thereby be deprived of their ordinary right to the moneys as being personalty or of the right to sue for the moneys in their own names (y).

A cestui que trust is entitled to bring an action against his trustee and compel him to perform any particular obligation under the trust. Thus, if the legal estate in the hands of the trustee be distributed by a stranger the cestui que trust, though he may not institute legal proceedings in the name of a trustee without his authority, may oblige the trustee, on giving him a proper indemnity, to lend his name for asserting the legal right (s).

(w) See chapter 11, Assignee of the Mortgage, Sec. Sec. 101 and 102.

(x) See chapter 24, Action for Foreclosure or Sale, Sec. 233, where the question who should be plaintiffs is more fully discussed. As to the persons entitled to discharge a mortgage, see chapter 19, Discharge or Reconveyance.

(y) Leith's Real Property Statutes, p. 420. As to the rights of the personal representatives, see chapter 13, Persons entitled on Death of the Mortgagee.

(z) Foley v. Burnell, 1783, 1 Bro. C.C. 277.

As a general rule no one is entitled to enforce a covenant except the covenantee or his assignee or personal representative, but'this rule is subject to exception if the covenant is entered into in such circumstances that the covenantee is constituted a trustee for a third party. If A covenants with B expressly as trustee that A will transfer property or pay money to B upon trust for a third party, then in the event of B refusing to enforce the covenant, the third party as cestui que trust has in equity the same right to sue A as B would have at common law, for in effect B is constituted a trustee of an executed trust of a legal chose in action (a).