If you are using the Professional version of the TANDM Suite, you can modify any mistakes before data is sent to the cloud. (see the App and Device Help page for details).
However, once the data is sent to the TANDM Suite admin page, data integrity is everything when it comes to achieving real results from your studies.
If amendments are a must, you can export your data to excel or chat with the team for adjustments and additional help.
(See How do I export my data to excel for further information)