Like many things in the law, it depends. In general, you can change your will without informing your spouse. (One big exception to this would be if one of you has filed for divorce and there is a restraining order on assets.) This can sometimes come up if there are marital difficulties and you want to make someone else the executor of your estate or perhaps you had a spouse’s family member listed as a beneficiary and want to change that. The real question is whether you can or should use the same attorney who drafted the wills for you and your spouse in better days.
Attorneys can only represent two clients in the same matter as long as there is full disclosure and agreement of all involved, so that there is no conflict of interest. Usually, when a couple comes in together to do their estate plan, I feel comfortable representing them both since they both have the same interests. I have them sign something saying they understand the conflict of interest issues and that I may disclose information from one party to the other.
In general, if you are wanting to change your estate plan to remove your spouse from certain documents, you would probably be safest to seek a new attorney and not use the same one who represented both you and your spouse. By helping you remove your spouse or change what they would inherit, the attorney could be taking an action that would be adverse to their other client, your spouse. This could possibly put the attorney in violation of their ethical duty or result in their needing to tell your spouse what is happening, as you agreed during the joint representation. By seeking an entirely new attorney, you can be assured that their sole loyalty is to you, and you don’t run the risk that they may need to disclose your plan to your spouse.