We have modified the popular Mbone toolVic (VIdeo-Conferencing) to use Arequipa (Application REQuested IP over ATM). The latter enables applications and in particular Vic, to request a direct ATM connection for its exclusive use and to directly control the traffic parameters of this connection. We have also implemented ATM Forum's UNI4.0 signaling and ITU-T's connection modification recommendation Q.2963.1, on end-systems as well as on switches. This implementation, coupled with the Arequipa mechanism, allowed Vic to negotiate and renegotiate ATM bandwidth at will, at run time. We describe how Vic accomplished that over the ATM WAN of SWISSCOM, transferring live video from Lausanne to Basel and Zurich over switched, renegotiable ATM connections. To our knowledge, this was the first time any application had the capacity to tune ATM traffic parameters at run time. Keywords: ATM, Arequipa, QoS, signaling, renegotiation, Vic