You can chat one-on-one with anyone who is the member of a group you own.
If you want to connect with someone but already have 4 Buddies, or you want to stay in touch with a previous Buddy
Create a public or private group
Go to their profile and Invite them to the group
On your group page, under Members click on the chat bubble next to their name to start a one-on-one chat
Or use the Group Chat for your group