Tax Year 2016: I din't deduct my rental property expenses for 2015 on last years return. Can I add these expenses to this years return ? If not what do I do?

[KarenL2]

Unfortunately, you cannot deduct your 2015 deductions on your 2016 tax return.  You will need to amend your 2015 tax return to include it. 

Amending is done on Form 1040X.  Amended returns have to be printed and filed by mail.  It can take the IRS up to 12 weeks or longer to process them.   If you are due a larger refund than on your original return, your amended return should only show the difference and you will receive a separate check for it.  If you owe money on your amended return, it will show only the new amount owed, you will have to mail a check with the return.

How to Amend?

https://ttlc.intuit.com/replies/3288565