I think we'd need a little more information to help you figure out if it's possible to create an automation for this. Can you explain the process more in-depth with each step of the ticketing process?

clients email our helpdesk email 
- email is broken into a spreadsheet in make.com
- Airtable listens to a new record in the spreadsheet and imports it
- our Customer Support team reviews the tickets, finds a solution and emails back to client view another integration with Make.com

- the above works well. As I stated in the original question - what we would prefer is that when the client replies to the response from out team, that the response gets appended to their original email. 

Yeap, you could trigger an automation to look for another record with that same email address and update that record.  You could then add a "Run a script" action at the end to delete the triggering record if you wanted to, and if you look on the forums you'll find examples of said script

Here's Airtable's guide on how to find and update a record: https://support.airtable.com/docs/use-automations-to-timestamp-status-updates

Thank you for your response. My question about searching for an email record would be a match that is an email address but is not a connection to a previous ticket, it could be a separate idea/issue. I think I would have to match to the subject or possibly the 2, email and subject? 

Yeap, that sounds right!

I understand how to create triggers. What I do not understand is how to set the trigger to fire only when the sender email and subject match an existing record. Where do I find/enter that logic?

That's not possible I'm afraid.  You'll need to use a "Find Record" action for that

OK, I see the find record feature. How do I match it against the message and the user email?

You'd use the 'Find Record' action to look for records with those values?  Sorry, I feel like I'm not understanding something here.  What difficulties have you faced attempting to set up the Find Record action?  Here's an Airtable guide that might help: https://support.airtable.com/docs/linking-existing-records-using-automations