Form United Baltic Provinces is the decision that forms 
United Baltic Nations.
It follows the requirements of the usual formation decisions. The forming nation needs to have Latvian or Estonian culture as primary culture, have 45 prestige and own/sphere all the Baltic cores. It also requires the forming nation to be at peace.
No independent nation can take the decision, but 
Estonia and 
Latvia can be released from 
Russia and take the decisions.
United Baltic Nations can also be released fully by Russia.