As Renan already noted, it depends on how your QoS is currently configured. Somethings nothing needs to be changed. I.e. this is a "it depends" answer.
However, also depending on the nature of the WAN link, and your overall QoS policy and other device QoS configurations, more than one device, including even those that don't directly "touch" the changed link, might also need to be reconfigured.
Also even when changes aren't required, with changed bandwidth, you might "rethink" what you QoS policy should be and make changes for that reason.
