preserves the ability of parties by agreement and trial courts by order to

adapt discovery to different circumstances. That ability is broad but not unbounded. Parties cannot merely by agreement modify a court order without the court’s concurrence. Trial courts cannot simply “opt out” of these rules by form orders or approve or order a discovery control plan that does not contain the matters specified in Rule 190.4, but trial courts may use standard or form orders for providing discovery plans, scheduling, and other pretrial matters. In individual instances, courts may order, or parties may agree, to use discovery methods other than those prescribed in these rules if appropriate. Because the general rule is stated here, it is not repeated in each context in which it applies. Thus, for example, parties can agree to enlarge or shorten the time permitted for a deposition and to change the manner in which a deposition is conducted, notwithstanding Rule 199.5, although parties could not agree to be abusive toward a witness. 2.