Vicki, I am not familiar with AZ but can tell you that, usually, once a state makes its determination the taxpayer has a window to file an appeal. Here your client did not receive notice but she also failed to update her address or file a return, so I do not seeing her getting out of it. I would look to see if the AZ DOR has a Doubt-as-to-Liability or Audit Reconsideration process.
Federally, you can always file a return to correct an SFR if it is still open for collections. If the IRS rejects it you can file a DATL or for Audit reconsideration using the returns as the basis. If it is not in collections because there is no balance due (the IRS got paid by levy or there was an over payment it kept), then usually it is 2 years because after that you can no longer get a refund of the moneys the IRS is holding.