
311 S.E.2d 362 (1984)
Ronald TAYLOR, Executor of the Will of H.E. Gillespie, (deceased)
v.
H.L. GILLESPIE.
No. 8317SC209.
Court of Appeals of North Carolina.
February 7, 1984.
*363 Folger & Folger by Fred Folger, Jr. and H. Lee Merritt, Jr., Mount Airy, for plaintiff.
Franklin Smith, Elkin, for defendant.
WELLS, Judge.
In his first assignment of error, defendant contends that the trial judge *364 erred in failing to allow his motion for a directed verdict at the close of plaintiff's evidence and at the close of all the evidence. A defendant waives his right to appeal the denial of a motion for a directed verdict at the close of plaintiff's evidence by offering evidence of his own thereafter. Gibbs v. Duke, 32 N.C.App. 439, 232 S.E.2d 484, disc. rev. denied, 292 N.C. 640, 235 S.E.2d 61 (1977). Although defendant also assigns as error that the trial judge failed to grant a directed verdict in his favor at the close of all the evidence, defendant does not support this assignment of error by arguments in the body of his brief. Instead, he states only that the trial judge was correct in determining that legal title to the Lincoln was in defendant's name. Assignments of error not supported by legal argument are deemed abandoned, Rule 28(a) of the Rules of Appellate Procedure. Defendant's first assignment of error is overruled.
In his second assignment of error, defendant contends that the trial judge erred by permitting plaintiff to amend his complaint to allege a resulting trust. Defendant argues that he was unfairly surprised by the change in theory of the case at the end of the trial, since the trust theory was not raised in the parties' pleadings. N.C.Gen. Stat. § 1A-1, Rule 15(b) of the Rules of Civil Procedure, provides:
.....
When issues not raised by the pleadings are tried by the express or implied consent of the parties, they shall be treated in all respects as if they had been raised in the pleadings.... If evidence is objected to at the trial on the ground that it is not within the issues raised by the pleadings, the court may allow the pleadings to be amended and shall do so freely when the presentation of the merits of the action will be served thereby and the objecting party fails to satisfy the court that the admission of such evidence would prejudice him...
A formal amendment to the pleadings "is needed only when evidence is objected to at trial as not within the scope of the pleadings." Securities & Exchange Commission v. Rapp, 304 F.2d 786 (2d Cir. 1962), cited with approval in Roberts v. Memorial Park, 281 N.C. 48, 187 S.E.2d 721 (1972). In the case at bar, defendant did not object to the introduction of evidence tending to establish the existence of a resulting trust. Because no objection was made to the introduction of the evidence, the pleadings were amended by implication. Formal permission of the court was not required, although the better practice is that the party benefitted should move to amend the pleadings to reflect the theory of recovery. Roberts v. Memorial Park, supra. By failing to make timely objection to the introduction of the evidence at variance with the pleadings, defendant has waived his right to assert this ground on appeal.
In addition to the question of amendment to the complaint, defendant raises the question of when a party to a lawsuit may seek to alter his legal theory of recovery. Defendant cites Goldston Bros. Inc. v. Newkirk, 234 N.C. 279, 67 S.E.2d 69 (1951) for the proposition that while a lower court may permit amendments to the pleadings within its sound discretion "... the cause of action as previously charted may not be substantially changed." Cases decided after Goldston and the adoption of the current rules of civil procedure permit a more liberal use of amendments to a party's theory of recovery. N.C.Gen.Stat. § 1A-1, Rule 15(b) of the Rules of Civil Procedure allows issues to be raised by liberal amendments to pleadings, and, in some cases, by the evidence, the effect of the rule being to allow amendment by implied consent to change the legal theory of the cause of action so long as the opposing party has not been prejudiced in presenting his case, i.e., where he had a fair opportunity to defend his case. Roberts v. Memorial Park, supra. While defendant may not have anticipated plaintiff's use of the trust theory, defendant has failed to show that he was denied a fair opportunity to assert his defense to plaintiff's claim.
*365 It is clear, however, that an amendment to the theory of a case is improper unless there is some evidence supporting the new theory. In the case before us, there was ample evidence that testator provided the money that paid for the Lincoln, and that he did so before legal title to the Lincoln passed to defendant. On these facts, a sufficient presumption of resulting trust arises. A resulting trust is one which arises by operation of law, based upon some action or conduct, rather than a direct expression of intent by the parties. Bowen v. Darden, 241 N.C. 11, 84 S.E.2d 289 (1954). A resulting trust may arise "... in the absence of circumstances indicating a contrary intent, where the purchase price is paid with the money of one person and the title is taken in the name of another, for whom he is under no duty to provide ..." Strange v. Sink, 27 N.C.App. 113, 218 S.E.2d 196 (1975), and where it is also shown that the payor gave the consideration before legal title in the subject of the trust passed to the other party. Byerly v. Byerly, 38 N.C.App. 551, 248 S.E.2d 433 (1978). Defendant's second assignment of error is overruled.
For the reasons stated, we find
No error.
BRASWELL and PHILLIPS, JJ., concur.
