Is it possible to change my information once I submit my tax extension?

you can always change your federal tax return, even after filing an extension of time to file. The IRS encourages taxpayers to file complete and correct tax returns. In the event you make a mistake or omission, however, you can always file an amended tax return. When you obtain an extension, it has no bearing on your ability to later amend that tax return. HOWEVER,you don't have an unlimited amount of time to correct your tax return and file an amendment on Form 1040X. Generally, the IRS limits the amount of time you have to file an amended return to the later of three years from the time you file your return or within two years of paying the tax for that year. Therefore, when you obtain a six-month extension to file the original return, you also receive an extra six months to amend it. For example, if you file your 2012 tax return on April 15, 2013, then you have until April 15, 2016, to file an amended return. But if after obtaining the extension you file the return on Oct 15, 2012, you can then file an amendment until Oct 15, 2016. There is a long list of acceptable reasons for you to file an amended tax return. Common reasons include omitting income that is taxable, choosing the wrong filing status, forgetting to claim a dependent or other deduction or to include a tax credit that you were initially unaware you qualified for. In most cases, you will either owe more tax with your amendment or be due a refund, depending on your reason for amending. If your amended return increases a refund, the IRS will send you the additional money after it processes your 1040X. However, if you owe more tax, you should pay it off as soon as possible since you will incur interest and penalties if it remains unpaid.