How to I pull text data from child table and 'combine' into a single text field at the parent level?

Kind of like a summary field for text. I need this for a report. 

For example - the parent table "jobs" that has 3 services. I want to pull the 3 "service names" into a single field ('service names') for the related "job". I want to combine the names into a single field for easy export. 

Thanks!