Hello Everyone, Could you please help us is there any API available to update the revenue plans for each revenue arrangement.

No there is no API to update the revenue plan. You need to manual by clicking the standard button. One way might be worked you need to check how the standard button works and extract the backend functionality and try to use it inside your side. (This might be a complex solution and out of NetSuite) Thanks Yagya

Have you tried the N/action module?