Const and for loop

In the following for statement: why doesn’t it matter that a and b are declared as const. I was under the assumption that we cannot reassign const values
let arr = [‘hi’, ‘hello’, ‘bye’]
for (let i = 0 ; i < arr.length ; i++) {
const a = i + 1
const b = arr[i]
console.log(${a}. ${b})
}

The variables are getting re-declared at each iteration of the loop.