Generally, when a partnership terminates for federal income tax purposes due to a sale of a 50% or more interest in the partnership, two things are considered to happen. First, the partnership will be considered to contribute all of its assets in-kind to a new partnership in exchange for an interest in the new partnership. You and the purchaser will be considered to receive that partnership interest in equal proportions.
Second, the old partnership will then be considered to go out of existence for federal income tax purposes.
The termination of  the old partnership and the deemed formation of  the new partnership should  not generally result in any gain or loss to you. However, depending on who  the purchaser of the partnership interest is, you may be precluded from continuing  the cash method of accounting.
We would be happy to discuss these consequences in detail and to discuss planning for the timing of the termination or, alternatively, methods for avoiding the termination.