[Asterisk-Users] BT-100 Transfer!!

[Altus Snyman]

Good day all
We have Grand Stream BT-100 phones
The transfer button work well, for blind transfer
What the users want to do is, when a call comes in and asked to be 
transferred to another extension,for example 100,they 1ste want to speak 
to exten 100,then have the option transfer or  not to transfer the call 
to this extension
Currently they must pus "flash" for a new line speak to the 
pearson,"flash" again and then transfer?
Any other or better ideas?
Please Help
Altus