CaptionCall gives you the ability to make a second call while already in a call and then merge the calls into a 3-way call.

While on a call, tap on the Gear icon in the call menu.

Tap on the Phone+ icon. This will place your current call on hold and allow you to dial a different phone number.

Once you dial the third party and the call connects, tap on the Gear icon in the call menu.

Tap on the Merge icon to merge calls.

Voilà! You should now be in a 3-way call. All parties will be captioned.

Happy calling!