When you delete an entity, it will also remove all relationships between the entity and events on the timeline.
Follow these steps to delete an entity from your timeline:
Tap on the entity type name or icon in the left Side Bar to open the entity list.
Tap Edit in the top right corner of the entity list
Select the entities you want to delete by tapping on the checkbox circle to the right of their name
Tap Delete in the top left corner of the entity list.
If you delete an entity by mistake, tap Undo in the toolbar to revert your last change.