Generally speaking, slow charge can not be changed into fast charge through transfer and other ways. The difference between fast charge and slow charge is the difference between the output power of the charger itself and the maximum power that the charging interface of the device can support.
Fast chargers typically have a higher output power, and the charging interface of the device also has a higher power input capability, which allows the device to be fully charged in less time.
However, if you use a slow charger, the charging interface of the device itself can only receive the output power of the slow charger, in other words, the charging interface of the device cannot receive the output power of the fast charger. Therefore, even if the adapter is used, slow charging will not become fast charging. If you want to use a fast charger, you will need to use the fast charger and charging cable that is suitable for your device.