Indeed, it is very exciting to bring aboard a person who has already served with us for a considerable time. This is not only exciting for us but also for him/her.
As mentioned, they might be aware of the normal proceedings and routines that we follow, so there is no need to focus much on that. However, if there have been any policy changes since the person left, ensure that those are communicated.
Welcome Day Arrangements
On his/her day of joining, you can gather the team members (whom he worked with previously) in the conference room, canteen, or another suitable area to give a grand welcome. If they are to work in a different team now, you can invite a few members from the new team as well. Such an informal introduction would lead to a better welcome, greater acceptance, and alleviate any fears about how the team might react.
Personal Touches
Consider decorating his/her desk or placing a welcome back card or something similar on the desk. You could also include chocolates or sticky notes with personalized messages from colleagues.
Make the welcoming process a little personal. A personal touch always helps
All the best.