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

Example Input: Sentence: 'a red stop signed has been altered to say stop hate'. Replace the letter 'e' with 't' in the sentence.
Example Output: a rtd stop signtd has bttn alttrtd to say stop hatt

Example Input: Sentence: 'wine is being poured into a wine glass with a syringe'. Replace the letter 'e' with 'y' in the sentence.
Example Output: winy is bying pouryd into a winy glass with a syringy

Example Input: Sentence: 'a giraffe stands next a brick wall and a door'. Replace the letter 'g' with 'u' in the sentence.
Example Output:
a uiraffe stands next a brick wall and a door