Hello,

First of all, enter the editing mode of the page where the Slider Revolution displayed. Check which one is used as shown here: http://prntscr.com/isshej

Then find this slider in the Slider Revolution plugin as shown: http://prntscr.com/issi0h

Finally edit the height in the slider settings as shown here: http://prntscr.com/isyjfv

You will find more manuals on how to edit slider as per your needs here: https://www.themepunch.com/revsliderjquery-doc/slider-revolution-jquery-5-x-documentation/

Best Regards