The legal colossus has used Edelman for the past five years, but is now on the hunt for fresh PR advice as profits for London-based law firms continue to decline.
Clifford Chance, based at Canary Wharf, has narrowed the search to six undisclosed agencies, which are expected to pitch later this month.
Edelman is one of the six agencies understood to be repitching. The account is believed to be worth approaching £250,000 in fees annually.
Clifford Chance global head of communications Claire Gosnell confirmed the pitch process was under way.
'Our PR requirements have changed since we first hired Edelman five years ago,' said Gosnell. 'We have changed the brief. The global legal media market has changed and become more competitive. The media have different expectations of law firms now and we want our PR to reflect our firm's priorities.'
Gosnell said she expected to have an agency in place by the autumn.
The brief is said to cover litigation support and corporate profile rising. One legal PR source said Clifford Chance was keen to establish a bigger corporate presence: 'Legal firms have suffered because of the economic crisis. It will want to invest in greater visibility the market. Competitor firms are equally trying to get cut-through and it is a very competitive market.'
Clifford Chance has offices across the US, Asia and Europe, and is a member of the 'magic circle', a term used to collectively describe a handful of the leading London-based law firms.
Several fellow magic circle firms have shown drops in revenue in recent weeks.
Clifford Chance was badly affected by the credit crunch because of the number of clients it has in the banking sector, including Lehman Brothers, Royal Bank of Scotland and Citigroup.
The law firm focuses on the core areas of commercial activity, capital markets, corporate and M&A, finance and banking and litigation and dispute resolution.