In case one came in late to prayer and has to pray one or more Raka'h after the congregation, is it permissible for him/her to step forward from the line toward a Sutra after the Imaam makes the salaam?

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.

If the steps that the person mentioned makes toward the Sutra are not many, there is no harm in this because of the need. The Sutra is an object that a praying person has in front of him so that his prayer will not be invalidated by anyone or anything intruding in to his prayer space. It is confirmed that the Prophet was praying to a wall, and considered it as Sutra, then a sheep wanted to pass in front of him, so he repelled it until he had to put his stomach against the wall, and then it passed behind him. [Abu Daawood] So this incident is an evidence that it is permissible to move slightly for a need. Imaam Ibn Qudaamah said: 'There is no harm in moving slightly during the prayer for a need.' Imaam Ahmad said: "There is no harm for a man to hold his son in an obligatory prayer, as it is reported in a narration that ‘Aa’ishah knocked on the door while the Prophet was praying, so he walked until he opened the door for her." But it is not permissible to make too many steps because moving during the prayer invalidates the prayer.

Allaah knows best.