On the asset entry worksheets for th rental, enter the date of "disposal" but no sales price.  This stops the dep as of that date and takes it out of service.  Print out the depreciation details sheet to save in case it becomes a rental again or gets sold, so you'll have the deprecation information.

Print the depreciation schedule for future reference and then delete the rental worksheets and depreciation schedules.

If I enter 01/01/20 as date of disposal, there is still a small amount of depreciation for 2020. Report it or delete the Sch E?

If they decided not to rent it it 2020, just delete it.

Iron Man hit the nail on the head again...

That's much better than the anvil hitting him on  the head again.

Absolutely!