Why did Greece need an extension of its bailout in February 2015?

In February 2015, the Greek government under Prime Minister Alexis Tsipras sought an extension of its existing bailout agreement to avoid immediate financial instability while attempting to renegotiate the terms of the country's debt crisis.12

Upon taking office in January 2015, Tsipras and his finance minister, Yanis Varoufakis, initially aimed to renegotiate the bailout terms to move away from the austerity measures implemented by the previous administration. However, after failing to secure support from other European leaders for a full renegotiation, the Greek government entered into talks with the "troika" (the European Commission, the European Central Bank, and the International Monetary Fund).12

To secure the extension, Tsipras agreed not to roll back the reform measures previously committed to by his predecessor. In return, the troika pledged to extend the bailout for four months, though they refused to release the final tranche of €7.2 billion until an agreement was reached on specific policy changes regarding taxation, labor rules, and pensions.1