Dear Jayaprakash Mageshwaran,
Good day to you! I hope you are doing well. Thanks for reaching out to our Microsoft Community Forum. We will be happy to help you.As per your description, you want to switch your excel sheet Web to desktop application which is located in SharePoint. I have tested from my end as result below.
Open the excel file in web > click on the Edting drowpdown >click on Open in Desktop.**If you can't find the option, please feel free let us know for further assistance.**Thank you in advance for your understanding. Your patience and cooperation are greatly appreciated.Best Regards,Nahid Sultan