If you tell people where to go, but not how to get there, you'll be amazed at the results.
George S. Patton
As a developers we are solution orientated. You have a problem and you try to find a solution. Off course you will try different paths but in the end you need to come with a solution.
As Scrum Master you have to switch that mindset. It's not you who need to solve the problem. It's the team that need to solve the problem. So let the team come up with solutions and enable them to do so.
We had a shift in priorities on the backlog and this meant to create a new team with a certain knowledge of the legacy application. But the decimated team was critical to deliver certain stories with dependencies which could block the other teams.
I organised a meeting with the teams to discuss the merger. Indeed I proposed a solution and wanted the team to help me implement this.
Luckily when I came into the meeting the team leads switched the orientation of the meeting and start discussing the issue. This enabled them to understand the problem and come up with possible solutions. We discussed all the possible solutions and finally we kept the teams as is. What we did was dividing the stories over the different teams to deliver them sooner.
This learned me a valuable lesson and let people amaze me with creative solutions. Just give them some room to do this. Don't forget we need to coach the teams not lead them!