What happens if your house isn’t finished when it’s time to switch loans?

Let’s say you’ve got a construction loan and the plan was to roll it over into a regular mortgage once everything’s done. But what if the build runs late (which, let’s be real, happens all the time)? Like, maybe the roofers disappear for a week or something gets backordered. Does the bank just extend the construction loan? Or do you end up stuck with some weird penalty fees or higher rates?

I’m just imagining being halfway through drywall and suddenly having to scramble for more cash or paperwork. Has anyone been in this boat before—or know what actually happens if your timeline gets blown up?