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

Example Input: Sentence: 'a train traveling through a dark tunnel next to green brush.'. Replace the letter 'r' with 'e' in the sentence.
Example Output: a teain teaveling theough a daek tunnel next to geeen beush.

Example Input: Sentence: 'two knives are embedded in a wooden table'. Replace the letter 'a' with 'l' in the sentence.
Example Output: two knives lre embedded in l wooden tlble

Example Input: Sentence: 'a bathroom with a white toilet next to a large window'. Replace the letter 'w' with 'x' in the sentence.
Example Output:
a bathroom xith a xhite toilet next to a large xindox