What is the status of the divorce proceeding here in CA? If the matter has been finalized and a Judgment entered, then your ex-wife can request to have the CA order registered in AZ. I am not familiar with Arizona Law, however she may be able to request to move the case to AZ and then request a modification. This process would involve a lot of legal arguments and requirements, and therefore may not be successful. If your ex-wife requests to register the order in AZ, I would recommend seeking an attorney immediately.
It is difficult to give accurate legal advice when all of the details of your case are not known. Please take this into consideration and consult a local attorney if you need additional assistance.
California has continuing and exclusive jurisdiction in this issue according to the UIFSA (Uniform Interstate Family Support Act). If she wishes to modify the support award, she will need to modify it in California.
This response is intended to be a general statement of law, should not be relied upon as legal advice, does not create an attorney/client relationship and does not create a right to continuing email exchanges