On change of the circumstances, you will need to write a letter to IRS and inform them about the need for update in your EIN status. Make sure you give enough time to IRS to decide your application. You will have to inform them clearly about the change of circumstances.
Provide all details to IRS in the letter. This includes the old and new address and other information that you want to update. Mark the letter with clear purpose of the change, and reasons why you want to update them.
In the letter, provide all legal details of the company, which includes name, address, registration and taxation details etc. You might be asked for provision of further information later. So, make sure you satisfy all the requirements of the IRS to get your application entertained. In some circumstances, the IRS might ask you to get new EIN.
Maintain a complete record of your communication and the documents that you have provided to IRS. Make copy each of them and keep in a proper filing system so that you can produce their proof at the time of their requirement.
It is likely that the IRS will inform you about the receipt of your letter. Keep the letter, and if you do not receive any further communication within stipulated time, contact the department again. You should quote the reference number in all your correspondence.
Maintain Updated EIN
On receiving updated status of EIN, maintain its record. Also, refer the new EIN details in you communications, as the updated EIN will replace all your previous details and will not be accepted as valid by the IRS or any other concerned department.