If you go into Forms mode, you can click on Open Form and type Schedule A into the search bar.
This will pull up your Schedule A calculations even if you are taking the Standard Deduction.
If you'd like to switch between the two deduction types:
If you go to Deductions & Credits, click I'll choose what I work on, and then scroll down to click Done with Deductions.
You will have to click through
a few screens, such as the summary screen for
your deductions and credits.
The Standard/Itemized deduction screen should come up soon after, along with a small
box to check if you'd like to change your deduction from standard to
itemized.