Question

the driver was blowing the horn convert in (passive voice)​

Answer 1

Active voice :

The driver was blowing the horn.

Passive voice :

The horn was being blown by the driver .

Here we have used being blown as the active voice is in past continuous tense and being along with participle gives the sense of past continuous tense.

How to change the voice of a sentence ?

1. Identify the subject and object.
2. Interchange the places of subject and object respectively.
3. Add the preposition by before the newly replaced subject.
4. Don't change the tense.

Eg : Active voice : She is painting a picture.

Passive voice : A picture is being painted by her.

Answer 2

the horn was being blown by the driver.