Change Microsoft Forms Ownership From Former Employees

This is really easy to do, but it took some digging to figure out.

As a global admin, go to https://forms.office.com/pages/delegatepage.aspx?originalowner=username@domain.com, where username@domain.com is replaced by—as you might have guessed—the former employee's UPN. I have found that the .onmicrosoft.com alias does not work here.

From here you can hover over a form, click the three dots in the corner, and then click Move to be prompted with slidover from which to select a destination.