Building change of use

A building in my town changed use from a place of worship (Jehova’s Winesses) to a Children’s Nursery. The building footprint is unchanged.
I managed to rename the building and its new purpose, but some unrequired fields about religion and service times cannot be removed.
How should I have moved from Facilities > Places of worship > Other … to …Facilities > Education > Pre-school without dragging the old fields into the mix?
As a newbie contributor to OSM, I’m anxious not to make any mistakes.
Kind regards,
Pete (Secretary of Prudhoe Pathforce Rights of Way Group)

Hi, In JOSM highlight/select the key/value then click delete. To correct or amend highlight/select the key/value the click edit, make the amendments, click Okay. I see you’ve already found this out and made the corrections, it looks OK to me.