A felling of stress take away the firs two letters then change one letter one from intention?

Removing the first two letters from "stress" gives us "ess." Changing one letter in "intention," such as replacing the "i" with "e," gives us "entention." However, if you meant to form a more meaningful Word, you could consider "tension," which relates to stress and involves changing the "i" in "intention" to "e" and dropping the last letter.