If a party failed to serve their expert disclosure statement on time, they may bring a motion pursuant to C.C.P §2034.710 for an order to submit a tardy expert witness list.  This section titled Power of Court to Allow Motion to Submit Tardy Expert Witness states:

(a) On motion of any party who has failed to submit expert witness information on the date specified in a demand for that exchange, the court may grant leave to submit that information on a later date.

(b) A motion under subdivision (a) shall be made a sufficient time in advance of the time limit for the completion of discovery under Chapter 8 (commencing with Section  § 2024.010) to permit the deposition of any expert to whom the motion relates to be taken within that time limit. Under exceptional circumstances, the court may permit the motion to be made at a later time.

(c) The motion shall be accompanied by a meet and confer declaration under Section 2016.040.

For the motion to be granted, the moving party must show:

1.     That the tardy submission was a result of “mistake inadvertence of excusable neglect”.    C.C.P. § 2034.720(c)(1)

2.     Relief was sought promptly. C.C.P. § 2034.720(c)(2)

3.     It served a proposed expert witness disclosure that is in compliance with C.C.P. §2034.260 on all parties. C.C.P. § 2034.720(c)(3)

4.     The expert(s) will be made available immediately if leave is granted. C.C.P. § 2034.720(d)

5.     The deposition(s) of the expert(s) can be taken before the discovery cutoff   for expert depositions.   C.C.P. §2024.040

6.     There is no prejudice to opposing party’s ability to respond to the new discovery.   Dickison v. Howen, 220 Cal. App. 3d 1471 at 1479-1480.

7.     A declaration that the moving party made a reasonable and good faith attempt to resolve the issue informally prior to filing the motion.   Section 2016.040

In considering the motion, the court must consider all of the above factors.  Denial based solely on the timing of the motion is an abuse of discretion.  See Plunkett v. Spaulding (1997) 52 CA4th 114 at 135-136.

If the court grants the motion, the court may also impose other conditions such  as:

• Allowing opposing parties to designate additional experts or to elicit additional opinions from previously designated experts.
• An award of costs and litigation expenses in favor of the opposing party .
• Order the moving party to pay for any additional cost to obtain an expedited deposition transcript.
• Ordering a continuance of the trial.

The statutes regarding expert disclosures are based on fair play so facts matter.  In bringing this motion, your need to convince the court that under your circumstances, the motion must be granted. If you are opposing the motion, keep in mind that the denial of the motion sets up an appealable issue. It is in everyone’s best interest that the parties meet and confer and agree on the conditions that the tardy submission can be allowed.