VanillaSoft makes it as easy as possible to bring up previously worked contacts by you. There are a few sections that would list the history of what you have worked. If you click on My CRM at the top of the caller screen, then My Stats, this will show all contacts that were worked by you on either the current day or the day before.
If you need to see contacts that were worked before yesterday, then you would have to either search for the contact manually, or run a report. Reports can be ran from the same My CRM section, just by clicking on My Reports and running one of the reports that has been built by your Admin.
Note: If you don't see any reports in this section, then an Admin will have to follow the steps in our Allow Callers Access to Reports article.