If something unexpected happens to an expert witness what are your rights about postponing the court date? Answer by attorney Michael R. Nack:
Part of the problem is that your change of heart may have come too late to correct. It may be that, if the trial date is coming up soon, it is too late to properly designate another expert to take your place. Some judges will not allow a delay in situations like this, and if your testimony is critical it is possible that your actions will cost his clients their case.
Even if there is still time to replace you and an adequate substitute can be found, replacing you will cost money and you will likely have to reimburse the lawyer for those funds. The new expert may charge more than you, for example, and the other side will expect to be reimbursed for the added costs and attorney fees involved in reading the new expert’s reports and taking his deposition. At the same time, your friend will have to perform additional work and you will be on the hook for his added fees. Even this limited exposure would be considerable in most cases.
Of course, the specifics of your situation might lead me to predict a less dire outcome. In general, though, experts who back out after they have been designated and deposed face some serious risks. You might want to re-think your position very carefully here, and first I strongly urge you to have a detailed consultation with a qualified attorney.
This question and answer regarding expert witnesses appears on Law Guru.com