I've got an additional field named accountnumber on my profile page that I need to keep track of if the user decides to change their accountnumber. When they change their account number, I need to take the original accountnumber to use it in a search where I store them on another site that I access via api. Example: user1 has accountnumber of 1234. user1 changes accountnumber to 5678. When the change is made, I need to grab 1234 to use in my api, when I find that 1234 exists I replace it with 5678. How can I go about doing this? using $user->accountnumber works to get the latest accountnumber but not the original(previous). Should I be doing this on the profile.phtml page or somewhere else?