P entered into a written contract with Tracer Research Corporation. The contract was for him to lobby on Tracer Research's behalf for exemptions of its tracers from regulation by the Clean Air Act. The contract provided payments to P based on the number of tracers that he was able to exempt from the EPA regulations. The EPA notified Tracer that 20 of its tracers '[were] not fuel additives' and therefore were exempt from environmental testing requirements. Tracer Research then became obligated to pay P $650,000 in fees. Tracer Research had already paid $30,000, so P alleged that Tracer Research still owed him $620,000. Subsequent to the formation of the contract and its alleged breach, Tracer Research was acquired by UCISCO, Inc., a wholly-owned subsidiary of D, and UCISCO thereafter changed its name to Praxair Services, Inc. Counsel for P stated by affidavit that after hearing of the sale, at the company website, he found a press release dated November 11, 2002, in which D., announced that 'Praxair Acquires Tracer Research' and which provided the details that 'UCISCO, Inc., a wholly-owned subsidiary of Praxair, Inc., has acquired Tracer Research corporation' and that 'UCISCO had changed its name to Praxair Services, Inc.' He also determined that Praxair Services, Inc., was not registered to do business in Maryland but that D., had been so registered. Both Praxair corporations were mentioned in the original complaint. D removed the action to federal court based on diversity jurisdiction and moved to dismiss the complaint on the ground that Praxair Services, Inc., not D, was the successor to Tracer Research's obligations under the contract with P. P filed an amended complaint and repeated the allegations contained in the original complaint but stated that Praxair Services, Inc., rather than D, was liable under the contract. He also alleged that D should be liable on an alter ego theory, and amended the caption of the case to indicate that both D, and Praxair Services, Inc., were defendants. D moved to dismiss because the complaint on its face was time-barred and Rule 15(c) did not provide relation back of the amended complaint. The district court granted the motion to dismiss. The court concluded that the relation-back provision of Rule 15(c) did not apply because the amended complaint did not 'change' a party, as required by the Rule, but rather added a new party, and that adding a party when P was fully aware of that party when he filed his original complaint was not the type of mistake envisioned by Rule 15(c) as suitable for relation back. P had not demonstrated that Praxair Services, Inc., 'knew or should have known that, but for a mistake concerning the identity of the proper party, the action would have been brought against it.' P appealed.