Changing shareholding within a company

A clients business is owned 75% by the father, 5% by the mother and 20% by their son.

They all work in the business in a full time capacity. At the moment the mother takes a decent salary on which she has to pay tax. They would like to realign the company share holding so they each have 33.3% in order to use dividends as an effective way of getting tax free payments out. They have asked me to rectify this.

However the business is profitable (£60k PBIT on T/O of £330K) and so obviously the shares have value.

How would one go about this with out creating capital gains and/or other tax liabilities?