If you have filed your return you can do an adjustment as soon as you receive your Notice of Assessment.

https://turbotax.community.intuit.ca/replies/2647992

Yes, the date range for medical expenses are reported to CRA as you can only choose a 12 month period, in which to claim your medical expenses.

The date range entered into TurboTax was Feb 1, 2017 to Jan 31, 2018. This was changed by TurboTax to Jan 1, 2018 to Dec 31, 2018. How do I change this with CRA & please correct your software to work correctly?

Where the receipts entered dated 2017 or 2018?

I only entered a total amount without any date & entered Feb 1, 2017 to Jan 31, 2018 as the year's range.