Seven letter words change one or two letter to make a new word

singing

longing

nothing

Gothics

Yup. Only the u changes to v.

In play:

hostile

Thanks. Had the shaky eyes last night.
shelter

shifter

flitter

flutter

reflate

inflate

Was going to use flinder, but MW says that there is no singular form for flinders.
plating

I might have used it before; it’s in several dictionaries.

plastic

elastic

spastic

pasties

satisfy

assists

bassist

assigns