Utilize the input text as a context reference, choose the right relationship between Syriza and Alexis Tsipras from the options. Options: 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.

While the new law will come as a relief to Prime Minister Alexis Tsipras -- who is negotiating a new bailout worth up to 86 billion euros ($93 billion) over three years -- it saw him suffer a major rebellion amongst MPs in his leftist Syriza party for the second time in a week.

Answer: chairperson