downgrade

A reduction of a rating, as a financial or credit rating.

A downhill gradient on a road or railway.

[...] dynamic braking is fitted to the 99-ton, 55 ft.-long locomotives to help control these otherwise vacuum-braked trains on the long, continuous downgrades encountered on the coastal route.

A reduction in quality; a descent towards an inferior state.

Near-synonyms: degradation, worsening, deterioration

To place lower in position.

The stock was downgraded from ‘buy’ to ‘sell’.

Basingstoke-Exeter will test this. From Salisbury westwards, it's largely single-track since British Rail downgraded it in 1967. There's a ten-mile loop between Templecombe and Yeovil, as well as shorter loops at Chard, Axminster and Honiton.

To reduce in complexity, or remove unnecessary parts; to dumb down.

More significantly, rigid deference to [Justin] Bieber’s still-young core fan base keeps things resolutely PG, with any acknowledgement of sex either couched in vague “touch your body” workarounds or downgraded to desirous hand-holding and eye-gazing.

To disparage.

We cannot afford to downgrade the lifestyles of other lesbians; we cannot afford to portray lesbians thinly as drunken and bothersome separatists who push their views on "work-within-the-movement" dykes".

Without downgrading my friends in the Building Trades, driving a nail or sawing a board is relatively simple.

to reduce the official estimate of a storm's intensity.

To revert software back to an older version.