The Federal Rules of Civil Procedure

Unless the court orders otherwise, the parties may stipulate that:

(a) a deposition may be taken before any person, at any time or place, on any notice, and in the manner specified—in which event it may be used in the same way as any other deposition; and

(b) other procedures governing or limiting discovery be modified—but a stipulation extending the time for any form of discovery must have court approval if it would interfere with the time set for completing discovery, for hearing a motion, or for trial.