A registered agent is a United States concept: a statutory appointee every company must maintain in its state of formation to receive official and legal mail. A UK process agent is contractual, appointed for specific agreements governed by English law. US companies signing English law contracts need the latter; their registered agent at home does not cover it.
The US registered agent
In the US, state law requires every corporation and LLC to designate a registered agent with a physical address in the state, on the public record, to receive service of process and official correspondence generally. The role attaches to the company's existence, covers whatever arrives, and continues as long as the company does. It is a compliance fixture rather than a deal term.
The UK process agent
England and Wales has no equivalent standing requirement for a contractual agent of this kind. Instead, the role is created deal by deal: an overseas party appoints an agent under a specific agreement, the appointment covers documents relating to that transaction only, and it lasts for the agreed term. That is why an American borrower on an English law facility is asked to appoint a UK process agent even though it already retains a registered agent in Delaware: the two roles simply do not overlap.
Which one do you need?
If your question is about maintaining a US entity, you need a registered agent in the relevant state, which is not a service we provide. If you are signing an agreement governed by English law and the draft asks for an agent for service of process in England and Wales, that is us: Tremark Process Agents has completed more than 10,000 such appointments since 1995, and US and Canadian clients are among our largest groups. See our dedicated page for US and Canadian companies.