Short answer. Yes. On a party's ex parte motion, the testimony of any person, party or not, may be taken by deposition through oral examination or written interrogatories, with the witness's attendance compellable by subpoena, following the specific procedure the Rules of Court set out for depositions.
What the law says
Upon ex parte motion of a party, the testimony of any person, whether a party or not, may be taken by deposition upon oral examination or written interrogatories. The attendance of witnesses may be compelled by the use of a subpoena as provided in Rule 21. Depositions shall be taken only in accordance with these Rules.
Rule 23, Section 1 — Depositions pending action, when may be taken. Read the full provision →
A deposition captures testimony outside the courtroom
A deposition lets a party obtain sworn testimony from a witness before trial, through either oral examination or written interrogatories. It is not limited to parties to the case — the testimony of any person, whether a party or not, can be taken this way, which makes it a tool for gathering evidence from witnesses generally, not only from the litigants themselves.
It can be sought on a party's own motion, without notifying the other side first
The rule allows a deposition to be taken upon ex parte motion of a party — meaning the moving party does not have to secure the other side's agreement, or even give advance notice through a contested hearing, before the court authorizes the deposition. This makes depositions a relatively accessible discovery tool once the case is underway, available to either side without needing the other's cooperation to get started.
A subpoena backs up a witness's attendance
A witness cannot simply ignore a properly noticed deposition. The rule provides that the attendance of witnesses may be compelled by the use of a subpoena as provided in Rule 21, tying the deposition process to the same compulsory-process machinery used to secure witnesses for trial itself, so a reluctant witness has no easy way to simply stay away.
Depositions follow their own procedural framework
The rule is explicit that depositions shall be taken only in accordance with these Rules — the process is not left to informal arrangement between the parties or their counsel. There are further specific procedures for how depositions are noticed, conducted, and later used in the case, and a deposition taken outside that framework does not carry the same weight as one taken properly under it.
A prisoner-witness needs the court's leave first
One category gets an extra safeguard: the deposition of a person confined in prison may be taken only by leave of court on such terms as the court prescribes. The general ex parte process does not extend automatically to a witness who is incarcerated — the court steps in to set the conditions under which that particular deposition can proceed.