You didn't specify your CUCM version, but iirc this has been pretty standard across versions. Just keep in mind that the menu options might be slightly different. Login to Cisco Unified Serviceability. From the menu, select Tools -> CDR Analysis and Reporting. From the newly opened window, select CDR -> Search -> By User/Extension. Depending on your configuration, you'll either enter a number for which you want to check call history in the Extensions field and press the Add Extension button to add it to the list, or click on 'Search Extension(s) based on User(s)' and search by user name.
Once the extensions list has one or more extensions listed, and you've selected the appropriate date range, press the 'OK' button. Keep in mind 2 caveats -- 1) This interface only retrieves 100 records at a time so you may need to run multiple searches. 2) The date range you enter in the initial search criteria is in UTC/GMT.
...of course this requires you to enable CDR (service parameters -> Call Manager -> CDR Enabled Flag. To enable CMR, hit the Advanced button and enable the 'Call Diagnostics Enabled' setting. The CDR records will show you placed/received calls as well as missed calls (i.e. the line is set to cfna to voicemail and you see the final destination of the call is voicemail -- that's a missed or unanswered call). The CMR data is accessed via the interface described in the first section above by clicking on the 'view' link at the far right column in the search results. It'll popup a new window with qos related data, endpoint addresses, etc.
