FC Leader Transfer

[Solarra]

How do you get lead back? Well, you can ask the present leader if they would be prepared to give the FC back to you but they are under no obligation to do so.
I doubt Square will interfere. If an FC leader goes inactive it leaves members in a potentially horrible position where they might not be able to access things like gardens or the FC workshop. To avoid that situation, lead is automatically passed to the next most active member after a period of time.

I understand that it's upsetting to lose control of something you have invested time and gil into, and I hate to be that person but maybe this is something you should have looked into more when you set up the FC. At least the new leader seems to be a decent person and you didn't return to find yourself kicked or the house sold, both things they would have been entitled to do.

Hopefully you can work things out amicably with them.