Need help change frequency

[mrel]

Hello
Does anyone know how to change the frequency of Brand name (UNINEX model VS-14 ) Video selector switch with remote control.
I purchase two of these video selector ,problem is the remote is control both video seclector box at the same time .
If I can change the frequency of one box at lease the other box will not control by the same remote.
The remote is Infrared type device.
Thank for the infor.
mrel