Does a change of business name constitute a change in legal entity for patent purposes?

No, a mere change of business name does not constitute a change in legal entity for patent purposes. However, it is still an important part of the ownership record. As stated in MPEP 314:

Although a mere change of name does not constitute a change in legal entity, it is properly a link in the chain of title.

This means that while the legal entity remains the same, the name change should be recorded to maintain an accurate chain of title for the patent.