This summary is not the rule. The rule text controls.
Here's a plain English summary of this rule:
Parties in a lawsuit can agree between themselves to change how discovery works, without needing to ask the judge first. Discovery is the process where both sides gather information and evidence before trial, like depositions (recorded interviews under oath), written questions, or document requests.
If both sides agree in writing, they can set their own rules for depositions. This means they can pick who runs the deposition, when and where it happens, how much notice is needed, and what format it takes. Once they agree to these terms, the deposition counts just like any other deposition taken under the normal rules.
The parties can also agree to change the timing or procedures for other types of discovery, like sending questions or requesting documents. However, these changes still have to follow certain time limit rules found in Rule 6(b).
The main point of this rule is flexibility. If both sides can work together and agree on a process, they don't need to get court permission for every small change. This can save time and money by letting people handle discovery in a way that works better for their schedules. But if the parties can't agree, or if the court decides to step in and set specific rules, then this flexibility goes away and the normal procedures apply instead.