Can i still amend 2017 tax return ?

was 2017 properly extended? if not the last date you could file an amended return would be 3 years after 4/15/2018 ie 4/15/2021.   if extended then you have until 3 years after 10/15/2018 ie 10/15/2021

You can file an amended return for 2017, but if the amended return shows a refund you will not get the refund unless you had an extension for your 2017 tax return. If the amended return shows a payment due, you still have to pay it.