Yes, you can generally change from an uncontested to a contested divorce at any point during the divorce proceeding.
At the onset of a divorce, parties oftentimes believe that their dissolution proceeding is uncontested based on informal conversations with their spouse. Usually unrepresented parties do not address all issues that need to be resolved in a dissolution proceeding during such discussions, based on their limited knowledge of the law. For example, maybe you and your spouse agree to “split everything 50-50” or “keep everything in each party’s possession,” but have not considered the logistics of how this will actually play out or the financial reproductions of such division.
Once parties realize that there are more issues than a simple 50-50 division, dissolutions often transition from uncontested to contested matters. Sometimes dissolutions also switch to contested matters once one party realizes that they may be legally entitled to more under the law than what they previously agreed to with their spouse.
Whether or not your dissolution switches to a contested matter, the divorce can still be resolved amicably prior to having the case proceed to trial. Generally when parties switch from an uncontested to a contested dissolution, the time and expense of the proceeding will increase. If the parties are adamant about resolving the matter amicably and with limited expense and money, this can usually be done even if the matter becomes contested.