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If your partner agrees to you withdrawing, then this would be rather easy. A contract would be drafted that has the partner withdraw (also an additional document for any shares to be sold at the time), and signed by both parties. Then the state is updated with the new owner's information /positions and the matter is over.
If the partner does not agree and no contract allows one to withdraw, then there is no choice but to go to Court. One can request that the Court dissolve the partnership, either for cause or without. If so, the Court will do this, but the litigation to this may be costly, so it is best if the matter is done without the court, in a buyout. Perhaps a threat to the other party to sue out of the partnership may be best to get them to agree to a voluntary buyout instead of fighting this in court which would hurt the business and the pockets of the individuals.
By the way when I say "buyout," it does not necessarily mean that lots of money must be paid. A buyout may be for a $1. It all depends on what the parties agree.
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