Conrad, the media agency that specialises in the travel industry, has worked with SHG brands for more than four years.
Agencies have been invited to pitch after a review of SHG's marketing strategy across all of its specialist brands, which include Crystal, Hayes & Jarvis and Citalia.
David Jarvis, the multichannel strategy director at SHG, said that the pitch aims to "get more effectiveness and efficiency from our marketing spend across all of our brands".
Matthew Prior, the managing director at SHG, said: "We have enjoyed working with Conrad for several years. Our group is growing and we are now looking to work with new partners to maximise our opportunities."