Change timing on the whole song?

So I just bought a song from a third-party company. The person who wrote the sheet that I bought made a mistake when he wrote it. The timing is badly off. All the notes that should be half notes are whole notes, all the notes that should be quarter notes are half notes, all the notes that should be eighth notes are quarter notes, etc. The length of notes he chose are all twice as long as they should be. So basically all I have to 'cut' all the notes in half. Is there any way to do that other than selecting every single note and rest and doing it one by one lol?