1. Get a free email adress at outlook.com if you do not have one.
2. Go to Skype and start a new account with your new outlook.com email address. Skype will ask you later in the registration process if you want to merge your old Skype account with the new one. This way you keep your contacts.
3. In Skype do a contact search with the email address that you use to sign into your Microsoft Lync Account and connect.
4. In Microsoft Lnyc accept the invitation from Skype.
Now you can call from Lync to Skype or from Skype to Lync.
Further Reading on how to avoid telephone and roaming fees:
How to avoid data roaming and roaming fees ? Mobile Wlan Hotspot devices (router/smartphones/…)
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