DC CODE § 45-401 provides:
(a) The common law, all British statutes in force in Maryland on February 27, 1801, the principles of equity and admiralty, all general acts of Congress not locally inapplicable in the District of Columbia, and all acts of Congress by their terms applicable to the District of Columbia and to other places under the jurisdiction of the United States, in force in the District of Columbia on March 3, 1901, shall remain in force except insofar as the same are inconsistent with, or are replaced by, some provision of the 1901 Code.

United States v. McKay 2 F.2d 257 further states:
Under the common law a man can change his name at will, provided it is not done with a fraudulent purpose; he may sue and be sued by such adopted name, and will be bound by any contract into which he enters in his adopted name. This is true in the absence of a restrictive statute, and is not abrogated by the fact that a procedure is provided by statute for the change of one's name. 20 Standard Ency. 250; In re McUlta (D. C.) 189 Fed. 250; Linton v. Bank (C. C.) 10 Fed. 894.

Kreuter v. United States, 201 F. 2d 33 further states:
In the absence of a statutory prohibition, a person, without abandoning his real name, may adopt or assume a name, and he may use such assumed name to identify himself in the transaction of his business, the execution of contracts and the carrying on of his affairs.

Affidavit