How do I alter the wiring from 3 phase to single on an electric motor

Buy the right motor

buy the right motor

Hi colin thanks your reply I already have a 3ph pump 220/400 volts the question I should have asked can I alter the wiring in the termnal box so it will run on single phase

No, you can't alter wiring. You need to generate 3 phase.

Depending on the Horsepower there are speed controls/phase converters that can be used.