I have my agent hosted in DialogFlow. Because of security reasons, I need to update DEVELOPER_ACCESS_TOKEN. I know there is a way to update CLIENT_ACCESS_TOKEN from settings. But didn't find any way to update DEVELOPER_ACCESS_TOKEN.
If your developer access token is compromised, you should create a new agent and transfer your intents and entities across.
If you are using this Dialogflow agent with Actions on Google and wish to continue using the API V1, you will need to create a new Action.
Alternately, consider switching your agent to use the API V2 Beta, which uses Google Cloud Service Accounts instead of API keys and will solve your problem.