In a classic sentence in the active voice, such as:
I canceled the ticket.
The agent, the person or thing doing the action of the verb appears as the grammatical subject, before the verb. The patient, the thing being acted on, appears as the grammatical object, after the verb.
To convert this to the passive voice, the patient becomes the subject, and moves before the verb, and a form of to be is used as an auxiliary verb, as in:
The ticket was cancelled.
This has the effect of hiding the agent. The agent can be shown in the passive voice, with a "by" construction:
The ticket was cancelled by me.
This third sentence conveys the exact same information as the first sentence did, but it is a bit wordier. It also stresses the patient, rather than the agent.
Because the passive voice requires the extra auxiliary, and can be used to hide or obscure the agent, it is sometimes used in poor or dishonest writing. That has given it a bad reputation. This is not really deserved, passive constructions are not ungrammatical, and sometimes they are the best way to say something. The passive should be used when the intent is to emphasize the patient, the thing or person acted on, and not the agent, the thing or person doing the action. Formal scientific writing uses the passive extensively, because the tradition is that suh writing should stress what is being done, and not who is doing it.
The passive makes it easy to say "mistakes were made", rather than "we made mistakes". Much stereotypical bureaucratic writing uses the passive voice. "Significant collateral damage was inflicted." instead of "Our army killed lots of people we didn't mean to." But that kind of evasive euphemism can be done in the active voice also, and that is just as bad. Just because the passive voice can be abuse is no reason not to use it properly.
I would say that the default for any given expression should probably be the active voice. The passive voice should be used when there is a good reason to do so. The previous sentence is an example, I wanted to emphasize the voice, and not the person. writing it. When you write a passive construction, consider, is there a good reason? If there is, great! Use it.
Oh, the original sentence:
It helps if I get a confirmation once the request to cancellation of the ticket has been updated
includes an error. "cancellation" cannot be used in this construction. One could write:
It helps if I get a confirmation once the request to cancel the ticket has been updated
Depending on the intended meaning "made" or "confirmed" might be better than "updated". One could also write:
It helps if I get a confirmation once the cancellation of the ticket has been completed.