Yes, all you are doing is replacing the forward to voicemail with another number. Firstly check what your voicemail forwarding is set to by entering *#61*11# and pressing the green handset button as if making a call. The first response should be something along the lines of 'voice call forwarding, when unanswered forwards to ********* Enabled where the **** is the number of your voicemail., make a note of this number as you may want to revert to it. Then you want to enter the following *61*{dest}*11*{sec}# where {dest} without the brackets is the full phone number you want the call to go to and {sec} is the amount of time in seconds that your pone should ring for, 30 is the maximum. Once that's done, retry the *#61*11# to check the status. If you want to revert to using voicemail for unanswered calls you redo the second command using the number you made a note of earlier in place of {dest}