The short answer is you can't, because the amino acid code is degenerate. The long answer is, you can get close, if you're willing to make assumptions about the specific transcript being used and guess at which mutation caused a specific AA change, as there are several different possibilities.

There are many previous questions about this (here is one: https://www.biostars.org/p/15992/)

The best tool I'm aware of is Transvar