This summary is not the rule. The rule text controls.
Here's a plain English summary of this rule.
An indictment is the formal document that lists the criminal charges against someone. This rule says a court can change small details in an indictment, like fixing typos or correcting minor wording, if there's a good reason for it. But the court cannot change the actual substance of the charge itself. In other words, the court can fix how something is worded, but it can't change what crime someone is actually being accused of committing.
Before allowing any changes, the court has to make sure the defendant still gets a fair chance to defend themselves. The defendant also can't be blindsided or caught off guard by the change. This protects people from being surprised by new or different accusations after they've already started preparing their defense based on the original charges.
If someone believes there's a problem or mistake in the indictment, they can't just bring it up casually in court. They have to file a written motion that spells out the specific defect they're pointing to. This keeps things organized and gives everyone, including the judge and prosecutor, a clear record of what issue is being raised and why.