Can a single phase generator run a 3 phase air conditioner?

Depending on who does the work it could be less expensive than getting a different air conditioner. The compressor will also need a capacitor and some rewiring. The old unit could have a 3 phase blower motor also which could run the price up even more. Although the changes can be made, the warranty at best will probably be a one year warranty and a new unit could have a 5-10 year warranty.