How can I add a new filter in the contact person search field?

To fill in new parameters please click on "search contact person". 

Here you can choose "Show advanced search and Filter" and choose the filter you want to change.

Please click on the little pen next to the drop-down field.  

Now you can change the parameters or fill in new ones, for example geographical details.

Please click "Save". 

Now you can use your changed filter.