change sides

change sides (third-person singular simple present changes sides, present participle changing sides, simple past and past participle changed sides)

1. to change one's loyalty from one team or group to an opposing one

   Synonym: switch sides

• choose sides
• turn one's coat
• turn tail
• change sides, change signs

• “change sides”, in Lexico, Dictionary.com; Oxford University Press, 2019–2022.
• “change sides” in Longman Dictionary of Contemporary English, Longman.
• “change sides” (US) / “change sides” (UK) in Macmillan English Dictionary.