Sure. Provided you have a 10mm socket and can "get to it," you can easily replace it. But it depends on where the main relay is located in your car. In some Honda vehicles, it's easy to get to. In others, it's hidden way back behind a bunch of other stuff and it's hard to find.

But if you can find it and get to it, there's only one 10mm bolt holding the bracket on. After you remove that bolt, the relay (attached to its bracket) will come out... still connected to its cabling.

Then, you just unplug the cable connector, plug the new relay (with bracket) onto the connector, and stuff it back in. If it looks like it's gonna be tough to re-mount the bracket, don't worry about it -- the relay is NOT grounded through the bracket. This means you don't HAVE to re-mount the bracket. You can just tuck it in and wire-wrap it to something so it won't jostle around.