Your presentation slide deck should be supportive of your presentation. This sounds logical but in practice you may come across a situation where the presenter skips a whole bunch of slides of his/her presentation. Don`t confuse your audience. If a slide is not being used then don’t include the slide in your presentation to show to your audience.
If the slide deck is prepared and provided to you by somebody else it is ok to delete the slides that you are not going to use. It is your presentation and you do not want to confuse your audience by showing them a bunch of slides that you are not talking about. Don’t show slides that you will not use in your presentation. Alternatively you can create one slide that shows a miniature version of the deleted slides of the original presentation and you can tell your audience that you will share these slides with them per e-mail for information purposes. This will obviously only work if these slides are self-explanatory.