What is the relationship between Skype and Microsoft in the context of the input sentence. Choose an answer from: product/material produced; manufacturer; distributed by; industry; position held; original broadcaster; owned by; founded by; distribution format; headquarters location; stock exchange; currency; parent organization; chief executive officer; director/manager; owner of; operator; member of; employer; chairperson; platform; subsidiary; legal form; publisher; developer; brand; business division; location of formation; creator.

Unify Square is recognized as one of the leading partners of Microsoft Skype for Business/Lync, currently impacting day-to-day operations of over 5 million seats at enterprises like Deutsche Telekom and Unilever.

Answer: operator