It is worth highlighting August 18 if you’re a Marriott Rewards member. That’s the day when Marriott International plans to integrate its three loyalty programmes (Marriott Rewards, Starwood Preferred Guest and The Ritz-Carlton Rewards) into one platform.

But on that date you may find yourself unable to book stays across its 29 brands and 6,500 hotels, as its sites and apps will shut down periodically to complete the global integration, which has involved 20 million new lines of code.

Speaking to Business Traveller’s  Middle East edition, David Flueck, Marriott International’s Senior Vice President of Loyalty, said that the work would start in the morning of August 18 (US East Coast time), and warned that “services will be intermittent”, adding that “we don’t expect it to last longer than 24 hours”.

Marriott advises members to book stays in advance, wait until later in the day or check the Free Night Award chart if they are considering whether to redeem before or after August 18.

Last month the group published its new free night award chart for the merged programmes, detailing every participating hotel and the points required for redemption before and after the August changes.

Although the ultimate goal is to integrate the three programmes into one singular brand, a new SPG app will launch, mirroring the functionality of the Marriott Rewards app, including Mobile Requests. All SPG members will receive a new 9-digit account number that aligns with the new system’s specifications.

Members will earn ten points per $1 spent on qualifying hotel charges; five points per qualifying $1 at Element, Residence Inn and TownePlace Suites hotels; and 2.5 points per qualifying $1 at Marriott Executive Apartments and ExecuStay properties.

Flueck said 70 per cent of its properties will “cost the same or are less expensive” under the combined programme.

As previously reported, the Marriott Rewards, Ritz-Carlton Rewards and SPG brands will continue to exist until early 2019, when a new single name will be announced for the unified scheme.