Historically, a dormant commission was given in relation to a military command. During the Crimean War, Sir George Cathcart held a dormant commission to take command of the British Army in Crimea if Lord Raglan was killed or disabled.
In Australia, the Governors of the Australian states, by convention, are given dormant commissions to act as Administrator of the Commonwealth in the absence of a Governor-General of Australia. By convention, the longest serving state governor exercises the dormant commission, allowing an assumption of office to commence immediately whenever a vacancy occurs and as long as it exists. For example, when Peter Hollingworth stood aside as Governor-General in May 2003, Tasmanian Governor Guy Green was appointed Administrator until Hollingworth's permanent replacement (Major-Gen Michael Jeffery) was appointed and sworn in. The Australian government can advise the monarch to revoke any Governor's dormant commission. For example, the dormant commission of Colin Hannah, Governor of Queensland, was revoked in 1975 after he made political statements which did not find favour with the government.
In New Zealand, the Chief Justice of New Zealand holds a dormant commission to act as Administrator of Government in the absence of a Governor-General of New Zealand. Other Commonwealth realms use dormant commissions in similar ways.