refederate
/ˌrɛfəˈdeɪteɪt/Definitions
1. verb
to join or unite again with a federation or confederation.
“The country decided to refederate with its former allies to counter the growing threat.”
2. verb
to form or establish a new federation or confederation.
“The neighboring states refederated to form a stronger alliance against common enemies.”
3. noun
a person or nation that joins or forms a federation or confederation.
“Several countries are considering refederating to create a new economic block.”