1.Invalidity benefits shall be converted into old-age benefits, where appropriate, under the condition laid down by the legislation or legislations under which they were granted, and in accordance with Chapter 3.
2.Where a person receiving invalidity benefits can establish a claim to old-age benefits under the legislation of one or more Member States, in accordance with Article 49, any institution which is responsible for providing invalidity benefits under the legislation of a Member State shall continue to provide such a person with the invalidity benefits to which he is entitled under the legislation which it administers until the provisions of paragraph 1 become applicable as regards that institution or so long as the person concerned fulfils the conditions for such benefits.
3.Where invalidity benefits granted in accordance with Article 39under the legislation of a Member State are converted into old-age benefits and where the person concerned does not yet satisfy the conditions required by one or more national legislations to receive these benefits, the person concerned shall receive, from this or these Member States, from the date of the conversion, invalidity benefits granted in accordance with Chapter 3 as if that Chapter had been applicable at the time when his incapacity for work leading to invalidity occurred, until the person concerned satisfies the qualifying conditions for old-age benefit laid down by the national legislations concerned or, where such conversion is not provided for, as long as he has a right to invalidity benefits under the legislation or legislations concerned.
4.The invalidity benefits provided under Article 39 shall be recalculatedpursuant to Chapter 3 as soon as the beneficiary satisfies the qualifying conditions for invalidity benefits laid down by a legislation not listed in Annex IV, part A, or as soon as he receives old-age benefits under the legislation of another Member State.