The sole question for our determination is: Did the trial court err in granting judgment for plaintiffs on the pleadings? We hold that it did.
 In Jones v. Warren, 274 N.C. 166, 161 S.E. 2d 467 (1968), it is said: “* * * The law does not authorize the entry of a judgment on the pleadings in any case where the pleadings raise an issue of fact on any single material proposition. [Citations] ”
 Judgments on the pleadings are not favored and a motion for judgment on the pleadings admits for the purpose of the motion the allegations of the adverse party and requires that such allegations be liberally construed. Tilley v. Tilley, 268 N.C. 630, 151 S.E. 2d 592 (1966).
 We think at least one issue arises on the pleadings. Article 6.4 of the contract provides as follows:
“If the Project is suspended for more than three months or abandoned in whole or in part, the Architect shall be paid his compensation for services performed prior to receipt of written notice from the Owner of such suspension or abandonment, together with Reimbursable Expenses then due and all terminal expenses resulting from such suspension or abandonment.”
In its further answer and counterclaim, defendant alleges that prior to the execution of the contract, defendant advised plaintiffs that the most it could afford for the total project was $175,000; that plaintiffs assured defendant they could develop the plans and specifications so that the total cost of the project would not exceed said amount; that after the contract was executed and plaintiffs had made further studies and calculations, they advised defendant that the project could not be completed for $175,000 but could be completed for $200,000; that relying on said assurance defendant advised plaintiffs to proceed to prepare the plans and specifications; that after the plans and specifications were completed they were submitted to contractors for bids and the lowest bid received, plus architectural fees and certain furnishings, amounted to $325,000.
*227Defendant contends that had it not been for the representations made by plaintiffs after the contract was executed that the total cost of the project under the plans and specifications they would prepare would not exceed $200,000, defendant would have abandoned the project at that point and not only would not be involved in the claim now made by plaintiffs but would have saved $4,152.00 paid to plaintiffs; that its decision to continue with the project provided a new consideration for plaintiffs’ subsequent agreement that the total cost of the project would not exceed $200,000.
Plaintiffs contend that the written contract specifically rules out guaranteed estimates of cost and provides that “ [t] his Agreement may be amended only by written instrument signed by both Owner and Architect.”
“ ‘The provisions of a written contract may be modified or waived by a subsequent parol agreement, or by conduct which naturally and justly leads the other party to believe the provisions of the contract are modified or waived. Mfg. Co. v. Lefkowitz, 204 N.C. 449, 168 S.E. 517; Bixler v. Britton, 192 N.C. 199, 134 S.E. 488. This principle has been sustained even where the instrument provides for any modification of the contract to be in writing. Allen v. Bank, 180 N.C. 608, 105 S.E. 401.’ Whitehurst v. FCX Fruit and Vegetable Service, 224 N.C. 628, 32 S.E. 2d 34.” (Emphasis added.)
We hold that defendant’s contention discussed above, fully supported by allegations in the pleadings, raises a legitimate issue rendering judgment on the pleadings in favor of plaintiffs’ error.
We do not say what other issues, if any, arise on the pleadings but leave that question for later determination by the appropriate tribunal.
For the reasons stated, the judgment appealed from is
Campbell and Vaughn, JJ., concur.