Yes, you can file taxes for 2016 before you amend taxes for 2015. You can follow the steps below to amend your return.
To File an Amended Return:
1. Wait for your return to be accepted or rejected by the IRS
2. Log into your account, and at your tax timeline select your "2015 Tax Year"
3. Select to "Amend (Change) 2015 return" and follow the directions
https://ttlc.intuit.com/replies/3288565
When I did my final review of this years taxes (2019), I entered my 3 children as dependents. I noticed when it showed last years dependents (2018) its show 0 dependents. How can I amend this? And also, will I receive any difference in my refund once updated?
See this Turbo Tax FAQ regarding How to amend your return.
You can file your 2016 taxes before you amend your 2015 taxes.
Steps:
To File an Amended Return:
1. Wait for your return to be accepted or rejected by the IRS
2. Log into your account, and at your tax timeline select your "2015 Tax Year"
3. Select to "Amend (Change) 2015 return" and follow the directions
You will not be able to amend your tax return until it has been accepted by the IRS. Please see the below FAQ for more information on amending a 2019 tax return:
https://ttlc.intuit.com/community/amending/help/how-do-i-amend-my-turbotax-online-return/00/27577