Question:
If someone is saying birchos krias shema (sitting down) and the tzibur has already begun shmoneh esrei, is one allowed to stand up to daven shmoneh esrei even though there is someone behind him already davening?
Answer:
You can stand up to daven shmoneh esrei, because you are already in front of him, but preferable not to take three steps back before you start (The Steipler never took 3 steps back).
Sources:
O:CH 95 Mishnah Berurah 3, Orchos Rabenu1:193
