What is the correct preposition required by the verb "to replace"?
Do "replace by" and "replace with" have the same meaning? Can they be used interchangeably?

For example:

My mother's replaced her old wardrobe by a new fitted cupboard.

OR

My mother's replaced her wardrobe with a new fitted cupboard.

Could you give me any more examples showing how this verb is actually used?

Question

What is the correct preposition required by the verb "to replace"?
Do "replace by" and "replace with" have the same meaning? Can they be used interchangeably?

For example:

My mother's replaced her old wardrobe by a new fitted cupboard.

OR

My mother's replaced her wardrobe with a new fitted cupboard.

Could you give me any more examples showing how this verb is actually used?

Answer

Francisco, your second example is correct. You could also say that she is replacing her old wardrobe FOR a new fitted cupboard. Some more examples: (A) the bumbling English professor is being replaced by a more competent one. 
(B) The mechanic decided to replace the old, malfunctioning engine with a new, fuel-injected engine.
(C) The dog feels as though he has been replaced by the cat.
(D) The little girl replaced her tiny tea set for a much larger one.

Answer

I would say "replaced with"

Answer

You use "by" if the verb is in the passive voice.  ("My mother's replaced her old wardrobe by a new fitted cupboard." is incorrect - it actually makes no sense.)

You use "with" if the performer of the action is neither of the objects in the replacement. ("My mother's replaced her wardrobe with a new fitted cupboard." makes sense.)

You don't use a preposition if the object which takes the new position is also the subject.

Some dictionaries will give sample phrases. http://www.thefreedictionary.com/replace

Non perdere l'opportunità di imparare una lingua comodamente da casa tua. Esplora la nostra selezione di insegnanti di lingue esperti e iscriviti subito alla tua prima lezione!