Combine the comments from UI and adding some more comments from a sub Process Model

Hi,

I have question on combining comments.

Scenario:

I have a section in UI where comments will be added and when clicks on submit, it runs a Process model and stores the comments in a CDT Field called Comments.

Here is the missing logic, when the Main process model runs and it runs a sub process model where we are inserting some more comments using a script task to store the comments in Comments field in the same CDT.

In the sub process instance, the CDT has both comments from UI and the comments which was assigned through script task, when we saw the instance of the Main process model, the CDT is populating only the comments which was from UI.

Looking for:  can you help me for any logic or solution we can display both comments in the CDT of main process model?

Thanks in advance