In this task, you need to replace a letter in the sentence with another given letter.

Example Input: Sentence: 'a woman is playing tennis on the tennis court'. Replace the letter 'r' with 'z' in the sentence.
Example Output: a woman is playing tennis on the tennis couzt

Example Input: Sentence: 'two police officers riding horses down the street'. Replace the letter 'o' with 'd' in the sentence.
Example Output: twd pdlice dfficers riding hdrses ddwn the street

Example Input: Sentence: 'a small yellow car going around a turn and a sign'. Replace the letter 'e' with 'z' in the sentence.
Example Output:
a small yzllow car going around a turn and a sign