When you manage someone, there's a formal structure underneath a hard conversation, even an uncomfortable one. With a peer, there's none of that, just two people who have to keep working together, with no one clearly in charge of resolving it.
The instinct many people default to is avoidance, working around the friction, routing communication through others, or just quietly tolerating it in hopes it fades. It rarely fades. Unaddressed peer conflict tends to calcify into a permanent low-grade tension that both people privately manage around for months or years, which costs more in the long run than a single uncomfortable conversation would have.
Peer conflict doesn't have a formal process to fall back on. That's exactly why it needs to be named directly, nobody else is going to do it for you.
The version that works starts with a direct, private, low-drama conversation, not an ambush, not something routed through a manager first, just a straightforward "can we talk about something" between the two of you. Framing it around the specific behavior or friction, not the person's character, keeps the conversation about something fixable rather than something personal.
"I wanted to talk directly rather than let this sit, I've noticed our last couple of project handoffs have had some miscommunication, and I think it's created some tension between us. Can we figure out a better way to hand things off, so we're not stepping on each other?"
That framing puts the process, not the person, at the center of the problem, which makes it much easier for the other person to engage without feeling attacked. Most peer conflict, even when it feels personal, actually traces back to a process gap, a miscommunication, or mismatched expectations rather than genuine dislike, and naming it that way often defuses more tension than either person expected going in.
If the conversation doesn't resolve things, or if the same pattern keeps recurring despite good-faith attempts to fix it, that's the point where involving a manager, yours, theirs, or a shared one, becomes reasonable, not a first resort but a next step after a direct attempt has genuinely been made. Framing that escalation around wanting help finding a resolution, rather than as a complaint about the other person, keeps it constructive rather than adversarial.
One thing worth remembering throughout: you don't need to become friends with every coworker you have conflict with. The goal is a working relationship stable enough that the friction stops draining energy that belongs elsewhere, not a resolved friendship, just a functional one.