
208 S.E.2d 251 (1974)
23 N.C. App. 21
Jerry L. CORBIN
v.
Charles W. LANGDON.
No. 7418DC448.
Court of Appeals of North Carolina.
September 18, 1974.
*253 J. C. Barefoot, Jr., Greensboro, for plaintiff appellant.
Younce, Wall & Suggs by Percy L. Wall, Greensboro, for defendant appellee.
MORRIS, Judge.
Plaintiff has only one assignment of error based on the only exception appearing of record. The exception is to the court's finding "as a fact that there is no genuine issue of fact to be submitted to the trial court in connection with plaintiff's claim asserted and (sic) the complaint filed herein."
Plaintiff first argues that the court failed to consider "parol evidence which is *254 admissible as completing and defining a vague contract." We do not argue with the principles of law espoused by plaintiff. He relies on Root v. Insurance Co., 272 N.C. 580, 583, 158 S.E.2d 829, 832 (1967), and quotes Justice Branch as having written for the Court:
"It is a well-recognized principle of construction that when the language of a contract is clear and unambiguous, the court must interpret the contract as written, Parks v. Oil Co., 255 N.C. 498, 121 S.E.2d 850, and "The heart of a contract is the intention of the parties, which is to be ascertained from the expressions used, the subject matter, the end in view, the purpose sought, and the situation of the parties at the time.' Sell v. Hotchkiss, 264 N.C. 185, 141 S.E.2d 259."
Plaintiff earnestly contends that it is obvious from his affidavit that the intention of the parties was that defendant collect the accounts receivable for the plaintiff. We are required first to look at the contract itself to ascertain the intention of the parties. Where the language is clear and unambiguous, the court is obliged to interpret the contract as written, Root v. Insurance Co., supra, and cannot, under the guise of construction, "reject what the parties inserted or insert what the parties elected to omit". Weyerhaeuser Co. v. Light Co., 257 N.C. 717, 719, 127 S.E.2d 539, 541 (1962). The contract before us is certainly not ambiguous. Rarely is a court asked to interpret an agreement as clear in its meaning as this one. The seller agreed to and did sell his dental equipment, furniture and fixtures to the purchaser for $18,000. The parties agreed with respect to fees during an interim period during which purchaser and seller practiced together. They then agreed that seller's accounts receivable should be included in the sale and that all amounts received from that source from and after 1 September 1970, the date of the contract, should be the property of purchaser. Seller then agreed not to compete with purchaser in the City of Greensboro for a period of two years, and purchaser agreed to assume the obligations of seller under a lease agreement then existing. It would be difficult to imagine a contract containing less ambiguity. It is obvious that the parol evidence seller seeks to have considered is not competent as explaining or completing or defining a vague contract, nor is it admissible to show the intent of the parties.
Plaintiff takes the position that the court should have considered the evidence as showing the practical interpretation given the contract by the parties and, therefore, competent evidence of their intent. Again, "[p]arol understandings, although they induce the making of a written contract, are merged in the writing so that they cannot be used to change the contract or show any intent different from that expressed in the instrument." 17 Am.Jur.2d, Contracts, § 261. The intent of the parties expressed by the entire contract is unambiguous. It is abundantly clear that the parties could have just as clearly expressed the intent for purchaser to collect the accounts for seller and pay the proceeds over to seller after retaining 25% for himself. This was not done, and the court could not properly consider any evidence which changed the intent of the parties as expressed in their written agreement.
Alternatively, plaintiff urges that the court should have considered the evidence as showing an amendment to the contract by oral agreement. It is true that the parties to a contract may, by a later agreement, rescind a contractin whole or in partamend it in any respect, add to it, or replace it with a substitute, if the original contract remains executory and if the parties in their later agreement, act upon a sufficient consideration. 17 Am.Jur.2d, Contracts, § 459. Here, at the time defendant says there was an amendment, the original contract was executory in at least one aspectthe time limit of the ancillary contract in restraint of trade had not expired. In all other respects, the contract was executed. *255 Assuming that this is sufficient to meet the test, plaintiff's own proffered evidence shows there was no meeting of the minds sufficient to furnish supportive consideration. In order to create a binding amendment to the contract, the same meeting of the minds is necessary that was necessary to make the original contract. Here plaintiff says, by his affidavit, that defendant on 26 October 1972, gave him a list of patients from whom collection had not been affected and said he wanted nothing further to do with collecting the accounts. Plaintiff says further that on 1 November 1972 he learned that defendant had sent mimeographed notices to all these patients advising them to make payment to defendant since all accounts receivable had been transferred to defendant "by written contract". This clearly negates any meeting of the minds on an amendment to the written contract.
"Rendition of summary judgment is by the rule itself, conditioned upon a showing by the movant (1) that there is no genuine issue as to any material fact, and (2) that the moving party is entitled to a judgment as a matter of law. G.S. § 1A-1, Rule 56(b); Kessing v. Mortgage Corp., supra [278 N.C. 523, 180 S.E.2d 823 (1971)]." Williams v. Board of Education, 284 N.C. 588, 599, 201 S.E.2d 889, 896 (1973), and cases there cited.
Here defendant relied on the pleadings and the contract itself and was entitled to summary judgment, nothing else appearing. Plaintiff's affidavits in opposition did not negate defendant's showing; but, on the contrary, buttressed defendant's position that there is no genuine issue as to any material fact. The contract is clear and unambiguous. It is completely clear with respect to the intention of the parties. The court correctly refused to consider evidence of any parol agreement made contemporaneously with the contract nor did it err in failing to consider evidence of an alleged parol agreement amending the contract where there is no sufficient evidence of mutuality of assent to support the agreement.
Plaintiff does not take exception to nor appeal from that portion of the judgment awarding summary judgment on defendant's counterclaim for $600. We note that by his complaint, plaintiff admitted that defendant had in fact, paid to him the sum of $600. See Pope v. Continental Insurance Co. of New York, 161 F.2d (C.C.App. 7th Cir.) 912 (1947). He again relies on the parol agreement made contemporaneously with the written contract.
We are of the opinion that plaintiff's assignment of error based upon his single exception is without merit.
Affirmed.
BROCK, C. J., and MARTIN, J., concur.
