C.O. Homes, LLC v. Cleveland, 460 P.3d 494

Landlord C.O. Homes and tenant Nancy Cleveland entered into an ORLTA-governed tenancy; tenant was to make monthly security-deposit payments and fell behind.
Landlord served two different termination notices: a 30‑day "for cause" notice under ORS 90.392 and later a 72‑hour nonpayment notice under ORS 90.394; each cited missed deposit payments but listed different amounts and cure deadlines.
Landlord filed an FED complaint attaching only the 72‑hour notice; tenant attended the first‑appearance hearing and filed an answer contesting the notice.
Two days before trial, landlord moved under ORCP 23 to amend the complaint to attach the 30‑day notice; the trial court allowed the amendment over tenant's objection and denied a continuance.
At trial the court granted a directed verdict for tenant as to the 72‑hour notice (invalid claim) but awarded possession to landlord based on the 30‑day notice; the Court of Appeals affirmed without opinion.
The Oregon Supreme Court reversed: allowing the pretrial amendment materially changed landlord’s claim and unduly prejudiced tenant, so the trial court abused its discretion; case remanded.

Issue	Plaintiff's Argument	Defendant's Argument	Held
Whether the trial court abused its discretion under ORCP 23 by allowing landlord to amend its FED complaint two days before trial to add a 30‑day notice (ORS 90.392) when the complaint attached only a 72‑hour notice (ORS 90.394).	Amendment merely conformed pleadings to evidence; tenant already had the 30‑day notice and suffered no prejudice; no new basis for recovery was added.	Amendment added a different statutory basis/notice and thus a new claim; tenant was prepared to defend only the 72‑hour claim and was prejudiced by lack of time and by prior strategic decisions (answer, exposure to fees).	Court held amendment improperly allowed: it substantially changed the claim for possession and unduly prejudiced tenant, so permitting it was an abuse of discretion; judgment reversed and remanded.

Elliot v. Mosgrove, 162 Or 507 (defines "claim" for amendment analysis — aggregate operative facts test)
Ram Technical Servs., Inc. v. Koresko, 346 Or 215 (explains use of Elliot definition in amendment context)
Foman v. Davis, 371 U.S. 178 (leave to amend generally "freely given" absent undue prejudice or futility)
Finney v. Bransom, 326 Or 472 (motions to amend are within trial court discretion)
Quirk v. Ross, 257 Or 80 (prejudice to opposing party is key factor in allowing amendments)
Oak Grove Parr v. McCutcheon Const., 275 Or 381 (amendment improper if it materially changes complaint or injects new element)
Humbird v. McClendon, 281 Or 83 (denial of amendment not an abuse where it changes theory of case)
Engelcke v. Stoehsler, 273 Or 937 (distinguishable: amendment after evidence was admitted without objection)