According to which Act, the title of viceroy was to be dropped ?

According to which Act, the title of viceroy was to be dropped ?

کس ایکٹ کے مطابق وائسرائے کا خطاب ختم کیا جانا تھا؟
Explanation

The partition was outlined in the Indian Independence Act 1947 and resulted in the dissolution of the British Raj, i.e. Crown rule in India. 

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Governor-General of Bengal (1773-1833):
When East India Company came to India, it controlled Bengal through a post named as "Governor of Bengal"
First Governor of Bengal: Robert Clive.
After the passing of Regulating Act 1773, the post of Governor
of Bengal was converted into "Governor-General of Bengal"
first Governor-General of Bengal was Warren Hastings.
Governor-General of India (1833-58):Charter Act of 1833, the post name of Governor-General of Bengal again converted into "Governor-General of India"
first Governor-General of India was William Bentinck.
Viceroy (1858-1947):
After the revolt of 1857, the company rule was abolished and India came under the direct control of the British crown.
Government of India Act 1858 passed which changed the name of post Governor General of India by Viceroy of India
The Viceroy was appointed directly by the British government.
The first Viceroy of India was Lord Canning.