to make convert from one to another as twisted curve - I mean the coordinates , you need before use rational number in sage math.
then you can easly use P.reduced(new_prime)
If will be one example code how to convert I will do all necessary.
try this Q
Provided Public Key: (55066263022277343669578718895168534326250603453777594175500187360389116729240, 32670510020758816978083085130507043184471273380659243275938904335757337482424)
The provided public key is valid on the secp256k1 curve.
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Twist Curve 1:
Order: 115792089237316195423570985008687907852837564279074904382605163141518161494337
Sub Groups: 115792089237316195423570985008687907852837564279074904382605163141518161494337
Small subgroups: []
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Using point Q = (55066263022277343669578718895168534326250603453777594175500187360389116729240, 110996999875816189248572145059526099470755853404867357109455384217806237834286) on Twist Curve 1
Partial private keys for Twist Curve 1
[]