Abstract: During generational change of exchanges, small relatively old exchanges (V2) previously working independently according to their own data banks (DBV2) are replaced by remote switching units (RSU). Said units are small independently working exchange and are assigned to central host exchanges (V), being controlled thereby, whereby data banks (DBV, neu) must be provided therein and the functionality thereof must include that of the data banks (DBV1, DBV2) of the previously separate exchanges (V1, V2). According to the invention, the data banks (DBV1, DBV2) are initially extracted from the exchanges (V1, V2), combined outside said exchanges and are subsequently completed with possible modifications of the original data banks (DBV1, DBV2). Said method runs automatically and allows planning data, for instance, to be incorporated. While the data banks (DBV1, DBV2) are being combined, operation remains substantially unimpeded to advantageous effect and read-only access to the old data banks (DBV1, DBV2) is possible.