$[$Stream ciphers are malleable$]$ Suppose that the message $$Pay $$1000$ to Bob$$ is encrypted using

a stream cipher as $7$e$4$d$6$c$73$d$5240$a$948$f$86951$bc$29481$a$5($in hex$).$ It is known that the plaintext

letters are encoded as $8-$bit ASCII characters. Provide a modified ciphertext such that its decryption

would read $$Pay $$9000$ to Bob$.$ Explain your answer.