transition comment in API

Is there a way to capture the transition comment within the API or better yet, without the API?  Here is my scenario.

User A sends a document from workflow state 1 to state 2

the user login is stored in the SubmitterEmail variable on the card

User B decides a change needs to be made and send the document back to state 1

my addin runs prestate change and sends an email to User A using the SubmitterEmail variable

SubmitterEmail is then cleared by the transition

I'd like the User B's comments from the transition of state 2 to 1 to be included in the email, but I'm not finding a way to capture this data.

Any suggestions?

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