der Wechsel
change / switch
A change in which something is replaced by something else.
Ein Wechsel des Stromanbieters kann viel Geld sparen.
Switching electricity providers can save a lot of money.

change / switch
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change / switch
A change in which something is replaced by something else.
Ein Wechsel des Stromanbieters kann viel Geld sparen.
Switching electricity providers can save a lot of money.

'Der Wechsel' (change/switch) is the noun form of the verb 'wechseln' (to change/switch). It always describes the exchange from one thing, state, or place to another.
Nach dem Studium stand ein Wechsel des Wohnortes an.
After university, a change of residence was coming up.
To describe the direction of the change, the structure 'der Wechsel von … zu …' (the change from … to …) is often used. The dative follows these prepositions.
Der Wechsel von der Schule zur Universität ist ein großer Schritt.
The transition from school to university is a big step.
'Wechsel' (change) is a very productive word and forms many useful nouns. Examples are 'der Wetterwechsel' (change in the weather), 'der Stimmungswechsel' (change of mood), or 'der Jahreswechsel' (turn of the year).
Der plötzliche Wetterwechsel hat viele überrascht.
The sudden change in the weather surprised many people.
In the context of banks, travel, or currencies, 'der Wechsel' (exchange) almost always refers to exchanging money. An important related word is 'der Wechselkurs' (exchange rate).
Vor der Reise nach England mussten wir einen Wechsel von Euro in Pfund machen.
Before the trip to England, we had to exchange euros for pounds.
The meaning as a financial instrument is outdated today. You will find it almost only in historical texts about trade and finance in the 19th and early 20th centuries.
Der Kaufmann bezahlte die Lieferung mit einem Wechsel.
The merchant paid for the delivery with a bill of exchange.
change
'der Wechsel' and 'die Veränderung' both have to do with something not staying the same. 'der Wechsel' usually means that one thing, person, or situation is replaced by another. So it is about exchanging something or switching to something else. 'die Veränderung' is more general: something becomes different without anything necessarily being replaced. It can be small or large, and often also profound in life, at work, or in a situation. Learners confuse these words because a 'Wechsel' is often a 'Veränderung'. But not every 'Veränderung' is a 'Wechsel'.

Nach dem Wechsel der Abteilung hat mein Kollege neue Aufgaben bekommen.
After switching departments, my colleague was given new tasks.
Die Veränderung im Team war am Anfang für alle ungewohnt.
The change in the team felt unfamiliar for everyone at first.