You can't "fire" a partner. Partners are owners not employees. If the partnership agreement is silent on the valuation of partnership interests, it will be necessary to negotiate with the non-contributing partner. It may be helpful to get a valuation of the partnership business. The value of the non-contributing partner's share is less than one-quarter of the value of the whole, because a minority interest in a business has no "control" over the business operations as the non-contributing partner can be out-voted by the other partners. If you can't reach an agreement with the non-contributing partner, it may be necessary to file suit to dissolve the partnership.