to hash out
transitive. To have a frank, thorough, or vigorous discussion about (something), with a view to resolving differences or reaching an agreement or decision; to discuss exhaustively; to go over (a topic, issue, etc.) again.
hash out, phrasal verb
1 or hash over : to talk about (something) : discuss (something)
The detectives hashed out their theories about who committed the murder.
They've spent quite a bit of time hashing over the problem.
We need to sit down and hash things out.
2 : to find (a solution) by talking Their lawyers hashed out a resolution.
3 : to solve (a problem) by talking We were finally able to hash out our differences.
thrash out, phrasal verb
: to talk about (something) in order to make a decision, find a solution, etc.
They had a meeting to thrash out their problems. thrash out a plan