Question: When was Burma's name changed to that of the country on the natural boundary between the country that hosted the tournament and the country where That Dam is from?

Knowledge 1: That Dam
That Dam (Lao ທາດດຳ, meaning Black Stupa) is a large stupa located in Vientiane, Laos. Many Laotians believe it is inhabited by a seven-headed nāga who tried to protect them from an invasion by the Siamese army in 1827. [SEP] Knowledge 2: Geography of Myanmar
Myanmar (also known as Burma) is the northwestern-most country of mainland Southeast Asia, bordering China, India, Bangladesh, Thailand and Laos. It lies along the Indian and Eurasian Plates, to the southeast of the Himalayas. To its west is the Bay of Bengal and to its south is the Andaman Sea. It is strategically located near major Indian Ocean shipping lanes. [SEP] Knowledge 3: 2018 FIFA World Cup
2018 FIFA World Cup Чемпионат мира по футболу 2018 (Chempionat mira po futbolu 2018) Tournament details Host country Russia Dates 14 June -- 15 July Teams 32 (from 5 confederations) Venue (s) 12 (in 11 host cities) ← 2014 2022 → [SEP] Knowledge 4: Myanmar
In English, the country is popularly known as either "Burma" or "Myanmar" i/ˈmjɑːnˌmɑːr/. Both these names are derived from the name of the majority Burmese Bamar ethnic group. Myanmar is considered to be the literary form of the name of the group, while Burma is derived from "Bamar", the colloquial form of the group's name. Depending on the register used, the pronunciation would be Bama (pronounced: [bəmà]) or Myamah (pronounced: [mjəmà]). The name Burma has been in use in English since the 18th century.
Knowledge 1: That Dam
That Dam (Lao ທາດດຳ, meaning Black Stupa) is a large stupa located in Vientiane, Laos. Many Laotians believe it is inhabited by a seven-headed nāga who tried to protect them from an invasion by the Siamese army in 1827. [SEP] Knowledge 2: Geography of Myanmar
Myanmar (also known as Burma) is the northwestern-most country of mainland Southeast Asia, bordering China, India, Bangladesh, Thailand and Laos. It lies along the Indian and Eurasian Plates, to the southeast of the Himalayas. To its west is the Bay of Bengal and to its south is the Andaman Sea. It is strategically located near major Indian Ocean shipping lanes. [SEP] Knowledge 3: 2018 FIFA World Cup
2018 FIFA World Cup Чемпионат мира по футболу 2018 (Chempionat mira po futbolu 2018) Tournament details Host country Russia Dates 14 June -- 15 July Teams 32 (from 5 confederations) Venue (s) 12 (in 11 host cities) ← 2014 2022 → [SEP] Knowledge 4: Names of Myanmar
Ma Thanegi records that the first use of the name 'Mranma' for the country is to be found on a 3 feet (91 cm) high stone inscription dated 597 ME (Traditional Burmese calendar) or 1235 CE. The stone is from the reign of Kyaswa, (1234 - 1250) son of King Htilominlo (Nadaungmya), Bagan. It is written in early Burmese script. Although the middle of the front side of this stone is damaged, the first line of the better - protected reverse side clearly shows မြန်မာပြည် (``Mranma kingdom ''). The inscription is known as the 'Yadana Kon Htan Inscription'. At present it is in Bagan recorded as stone number 43 in the Archaeological Department's collection.
Knowledge 1: That Dam
That Dam (Lao ທາດດຳ, meaning Black Stupa) is a large stupa located in Vientiane, Laos. Many Laotians believe it is inhabited by a seven-headed nāga who tried to protect them from an invasion by the Siamese army in 1827. [SEP] Knowledge 2: Geography of Myanmar
Myanmar (also known as Burma) is the northwestern-most country of mainland Southeast Asia, bordering China, India, Bangladesh, Thailand and Laos. It lies along the Indian and Eurasian Plates, to the southeast of the Himalayas. To its west is the Bay of Bengal and to its south is the Andaman Sea. It is strategically located near major Indian Ocean shipping lanes. [SEP] Knowledge 3: Myanmar
In 1988, unrest over economic mismanagement and political oppression by the government led to widespread pro-democracy demonstrations throughout the country known as the 8888 Uprising. Security forces killed thousands of demonstrators, and General Saw Maung staged a coup d'état and formed the State Law and Order Restoration Council (SLORC). In 1989, SLORC declared martial law after widespread protests. The military government finalised plans for People's Assembly elections on 31 May 1989. SLORC changed the country's official English name from the "Socialist Republic of the Union of Burma" to the "Union of Myanmar" in 1989. [SEP] Knowledge 4: 2020 AFC U-23 Championship qualification
Of the 47 AFC member associations, a total of 44 teams entered the competition. The final tournament hosts Thailand decided to participate in qualification despite having automatically qualified for the final tournament.

Answer: 1235