There will be always the time when you’ll need to make changes in your teams. This may be due to change in workload, people joining or leaving the group, change of methodology, etc.
We also had this situation in our office. In our case we were beginning to move towards a more agile model plus we were moving to a new office space. As we wanted to have more cross-functional autonomous teams, we thought this could be a great opportunity to take our next step. But how to do it?

It was very early stage in our transformation of culture so we needed to be careful but at the same time we wanted to use this opportunity to send out a message in the right direction.
The traditional approach would have been easy. We could have told a couple of people to change teams and desks and that would have been it. But how was this solution aligned to our new philosophy based on feedback and self-management? Nothing.
Instead we went down to the bazar where we often go for inspiration. They’ve got so many things there that the probability of finding a solution for your problem is high.
It was Xmas time, so the bazar was full of Xmas motives. The usual, Xmas trees, tinsel, balls, stars and all sorts of glittery stuff. We looked around for a while and then it stroke us.

This is what we did:
-We bought as many Xmas trees as teams we wanted to create
-We bought a Star for every PO we had
-We bought a tinsel for every QA we had
-We bought as many balls as developers we had
We were about to transform the office and we were aware that the impact could be significant. We did it by surprise on a Monday morning. We brought up the Xmas trees and put them in front of everyone and explained that we needed to reshape the teams to accommodate recent changes and also to prepare for what’s coming ahead.
We cleared everyone schedules for the day and decided to invest the day in going through this exercise in the best manner we could think of. We named the trees as Team A, Team B and Team C.
We asked the POs to take a star, Devs to take a ball and QAs to take a piece of tinsel. The instructions were simple, they needed to decorate the trees in a way that they all had all elements.
Sure this implied that each team will get one of the POs, each team will get one of the QAs and the a few developers each; but we believe that this way it would be more engaging than imposing some new teams made by management.
We went several times, let the teams repeat the exercise with different configurations and took pictures of it. Then we showed the pictures and they all voted for the best combination of team members and skills and the new teams were born. Scrum masters were assigned by draw.
Next step would be to create team identities. We encouraged the teams to spend sometimes thinking about their new name, their logo, their values and prepare a short presentation to introduce the new team to everyone.
This was a very positive exercise, new team mates started working together in a fun project. Even couple of teams decided to look for complementary names as they were going to work on the same product.
Once the teams had their identity, they needed to decide how to distribute the desks. You can imagine a huge mess of people fighting for the window or the best desk by some personal criteria. In fact, none of this happened. We gave them a floor map of the office and made paper balls with different colours. Each colour represented a team and asked the teams to work together around the map to place the paper balls in a way that everybody is happy. They did in under 20 minutes with no major issue.
The rest of the day was spent getting settled in the new desks, discussing on sprint format with Scrum Master and for POs to rearrange backlogs for each team. By Tuesday morning, all teams were planning the sprint and getting on it.
Was everybody happy? of course not, we crashed their teams, their previous identity, they lost their loved desk and nobody likes changes. But it needed to be done and this is the least disruptive and fun way we could think of.