You need to know how your system is setup for this first
LD 21
Req: Prt
Type: RDR
<cr>
Look for CFN0, CFN1, CFN2. The numbers for these prompts is the # of rings before transfer to whereever FDN is Set.
On the set side, the prompt RCO refers to CFN. RCO-0 = CFN0, RCO-1 =CFN1, RCO-2 = CFN2. If the CFN prompts are not what you want you can change them in LD 15
Req: CHG
type: RDR
CFN0: (enter the new parameter)
CFN1: " "
CFN2: " "
Remember - any changes to these prompts affects all the phones with the associated RCO parameter.