REST Call To Failover Mirrored Topic

Using this URL to POST /clusters/{cluster_id}/links/{link_name}/mirrors:failover - is the : between mirror and failover right? Also I am using the destination cluster id. What REST URL do I use the source or the destination? I tried the destination and received this error: ERROR 404 on path /clusters/{cluster_id}/links/{line_name}/mirrosr:failover