Oh boy! Yes, I have done this personally and I have had teams where I brought people back. I did this in 2011 actually, I joined a team that I had built most

Oh boy! Yes, I have done this personally and I have had teams where I brought people back. I did this in 2011 actually, I joined a team that I had built most of the original systems 7 years prior but now a whole new team of people were working on them. Only people that were the same were the CIO, president and a few others from different departments. So it was an interesting challenge because everyone thought I was a threat to the director/manager level people, when the reality was all I was there to do was write some code. Best thing for you to do is to make sure the current lead sees you as an ally and source of historical knowledge that can prevent her from looking stupid or hitting preventable issues. The way you can work on that is to show support for her and provide background or knowledge but be open about changes and don't get defensive over changes. The worst thing you can do is become defensive which even if you are right in a stance will isolate you, or worse fracture the team into factions of them and you. So instead of saying we can't do X, say something more like, well if we do that we will need to likely address X, Y and Z. The point being you don't want to be a roadblock or a naysayer, you want to be a team player and of course you want to try and prevent stupid from happening but do so in a non-confrontational way. Also, when discussing issues don't always reference when you were there before. Just use your knowledge to help but not as a crutch or stick, and ask lots of questions so people will feel you value them regardless of if they are new or been there the whole time. Hopefully that makes sense. The goal is to make yourself valuable to the team lead and team overall, but do so without using your past knowledge as a hammer. Use your knowledge as historical information that can help the team but don't be an obstructionist which is what I have seen a lot of in the past with people.