There are various call transfer scenarios to consider:

1. If you have multiple calls on hold and you want to transfer a connected call to one of the held calls:
Press the Transfer soft key and use the up arrow up and down down arrow arrow keys to select the desired call appearance. When you are satisfied, press Complete to transfer the call while the other held call(s) remain on hold.
2. If you have calls on hold but you want to connect your current call with a new destination:
Press the Transfer soft key and enter the destination manually using the numerical keypad and press Complete. Alternatively, press Dir to select a destination from the directory or use the Redial option, if applicable.
3. If you have a destination call connected but you wish to refer back to the originating call before completing the transfer:
Do NOT press Complete to transfer the destination call as in scenario #2. Select the originating call ('on hold pending transfer') by pressing its call appearance button. This will place the destination call 'on hold pending transfer' so that you can notify the originating caller.  With the originating call connected, you can now press Complete to connect the two calls. Held calls that are not pending transfer will not be affected. Moreover, it is not possible to have more than one call 'on hold pending transfer.'

Note: It is also possible to transfer a held call by starting a conference and then dropping yourself from that conference.  However, if you are the only internal user in the conference, depending on your telephone system's configuration, dropping yourself might end the conference.