He works as a collector for an electricity company. Is it permissible for him to change the currency before giving the collected money to the company?

No File Exists
Check below answers in case you are looking for other related questions:
Editing a book containing pictures
He acquired some wealth by means of haraam shares; how should he get rid of it?

No File Exists
Related Answers:
Money earned from doing forbidden things
He adds his brother’s produce to his own so that the government can market it without (the government) knowing
He died and left behind wealth on which he did not pay zakaah, and interest
Editing a book containing pictures
He acquired some wealth by means of haraam shares; how should he get rid of it?

Recommended answers for you:
Will a woman who does not wear hijaab go to Hell?
Ruling on drinking beer
Ruling on praying in a garment on which there is a picture of an animal or a person
Can the Prophet (peace and blessings of Allaah be upon him) hear those who call upon him when he is in his grave?
Deobandis