The phrase "in the rear" can have a negative connotation, as it is often associated with being last or trailing behind. However, there are several synonyms that can be used to communicate the same idea without the negative undertones. One option is "at the back," which simply describes the location without any judgement. Another possibility is "behind," which can also convey that something is after or following something else. "Trailing" is another alternative that captures the same sense of being behind or following. By using these synonyms, you can communicate the same information in a neutral or positive way.