[18][19] Díaz expressed her will to shape a new electoral platform transcending political parties, as well as the Unidas Podemos brand,[20][21] aiming to secure the support of ideologically close forces such as En Comú Podem (ECP), Compromís and Más Madrid/Más País while giving a prevalent role to civil society.

[22][23][24] The platform was drafted during an event held on 13 November 2021, with the participation of a number of female representatives of the various political spaces that could eventually join it: Díaz herself, Barcelona mayor, Ada Colau (BComú), Valencian vice president Mónica Oltra (Compromís), Madrilenian opposition leader Mónica García (Más Madrid) and Ceutan councillor Fatima Hamed (from the Movement for Dignity and Citizenship, MDyC); the absence of Podemos members at the event, most notably of Equality and Social Rights ministers Irene Montero and Ione Belarra, was seen as evidence of the growing diminished role of Unidas Podemos within the platform.

[25] The Díaz-led incoming left-wing alliance was also welcomed by incumbent prime minister Pedro Sánchez, who saw it as important for the "progressive space" to be in "top shape" in order for his government to be able to maintain and expand its majority in the next election.

[29] After its postponement as a result of the international crisis sparked by the 2022 Russian invasion of Ukraine, it was announced on 18 May 2022 that Díaz's platform would go under the provisional name "Sumar" (English: Unite),[30][31] with its formal launch being scheduled for after the 2022 Andalusian regional election.

[35][36] The event had an audience of over 5,000 people, with the attendance of relevant figures in the Spanish cultural landscape such as James Rhodes, Elvira Sastre or Belén Gopegui.

[46] The nationwide encounters of Díaz with the public continued in A Coruña,[47] Zaragoza,[48] Tarragona, Barcelona,[49] Palma de Mallorca,[50] Valladolid,[51] Albacete[52] and Murcia.

[15] Among the main parties present in the event were United Left (IU), Más Madrid, Compromís and Catalunya en Comú, but it was noted the notable absence of Podemos due to divergences with Díaz over the process to elect the platform's candidates.