I pressed the Jabra Link 400 button and unintentionally put the Jabra Engage 55 in pairing mode. What should I do?

Turn off the headset and then turn it back on. The headset will reconnect with the Link 400.

Note
If the Engage 55 and Link 400 were purchased as a bundle, then they are already pre-paired. When the headset is on, it will automatically reconnect to the Link 400. There is no need to press the Link 400 button.