The charity held chemistry meetings with a number of advertising agencies this week.
Agencies have been briefed to create advertising around the rebrand, the identity for which has been developed by Circus, an integrated brand consultancy company.
The charity does not have an incumbent advertising agency, but instead has a roster of direct marketing and digital agencies to work on specific projects, which includes Rapp and Profero.
Last October, Unicef called a pitch to find a direct marketing agency to work on a campaign to increase donations through its donor fundraising programme.
A spokeswoman for the charity said: "Unicef UK is in the process of reviewing its communication agency support. A number of chemistry meetings are taking place over the next few weeks. The direct marketing agency Rapp is unaffected by this process."