It sounds like it was supervised administration for a number of reasons, either the will required it, or if there was no will, the Judge thought it was a good idea. If you want to amend or modify the type of administration, you need to file the appropriate motion in Court providing for the proper notice and explaining the proper reasons required under the relevant statute.
Based on the limited amount of information provide, this advice is not complete and an attorney should be hired to assist you with this matter.
You must apply for court permission for any transaction above $10,000. Submit an affidavit in support of the motion. Regarding the sale of property, there is a motion you must make for the court to allow the sale of the property. Submit the signed contract along with the motion.
If you want the limitation removed, you must ask the court and support it with a motion on how it impedes your administrating duties. You may want to get waivers from all other beneficiaries in support.