What is the ruling on leaving to the right or the left for one who is sitting in front of someone who is praying?

Leaving to the right or the left of one who is praying is not regarded as passing directly in front of him.

We put this question to our shaykh, ‘Abd ar-Rahman al-Barrak (may Allah preserve him), and he said:

This is not passing directly [in front of one who is praying], because he is already there, and passing in front of someone means coming from side to side. End quote.

Shaykh Ibn ‘Uthaymin (may Allah have mercy on him) said: What is required of one who wants to pass in front of someone who is praying, in the Haram or elsewhere, is to wait until he has finished his prayer, or to pass him on the right or on the left, and not cross directly in front of him. If he passes him to his right or his left, then he is not passing directly in front of him. What is meant by passing directly in front of one who is praying is crossing right in front of him." (Fatawa Nur ‘ala ad-Darb  8/2).

And Allah knows best.