OpenAI does not offer the option to change or update the phone number associated with your account. This is true for ChatGPT and the OpenAI API.

If your concern is related to phone verification for generating your first API key, it's important to note that phone verification is required only for the initial API key generation on platform.openai.com. However, changing the phone number used for this verification is not supported. For more details, you can refer to our Phone Verification FAQ.