Use Class B1 (business) comprises offices (other than those that fall within A2), research and development of products and processes, and light industry appropriate in a residential area. In all cases it is a use which can be carried out in any residential area without detriment to the amenity of that area by reason of noise, vibration, smell, fumes, smoke, soot, ash, dust or grit.
Use Class B1 premises can benefit from permitted development opportunities to change use without requiring a full planning application. There may be a number of conditions and limitations to such a change however, and further detailed information about this can be found here on the Planning Portal website. This website also details other restrictions to permitted development that may be in place, such as planning conditions or Article 4 Directions, and it is recommended you get confirmation from the local planning authority about changes of use proposed using permitted development rights.
If a B1 premises does not benefit from permitted development rights, planning permission may be sought to change it to another use. You can learn more about this process here.