The phrase "need not entail" is grammatically correct and can be used in written English.
You can use it when you want to express that something is not necessarily required or does not necessarily lead to a specific outcome. It can also be used to indicate that there is an exception to a certain rule. Example: "In order to be successful, obtaining a college degree is often seen as a necessary step, but this does not necessarily entail that it guarantees success in one's career path."
"Regular" succession planning need not entail identifying potential successors.
That need not entail a flat-out rejection of the possibility of self-improvement.
But paying attention to desire and sexuality need not entail a theoretical paradigm of reproductive fitness.
Successful collaboration thus need not entail completely overhauling content courses so as to make library instruction the centerpiece.
Newness need not entail the rejection of older styles but rather depends on the preservation and extension of all styles.
The journey through what Pirsig called "the high country of the mind" need not entail outdoor camping or bad coffee.
The effect needn't entail anything like realism.
(It should however be noted that while theses under the description of pluralism needn't entail a commitment to relativism, some formulations of relativism (such as Boghossian's 2006b), include, as an essential ingredient, a "pluralist" clause.
Getting good lines needn't equate to likeability, however, and empathy needn't entail forgiveness.
In fact, as the psychologist and meditation teacher Tara Brach points out, the "radical acceptance" of mindfulness needn't entail resignation or narcissism; on the contrary, it embodies a refusal to dwell in comforting illusions, and may thus be an essential precondition for positive change.
Such departures, it may be noted, can thus include curvilinearity which needs not entail changes in rankings; but such curvilinearity, while it may be of interest mainly for how it affects resolution of genotypic differences among the best genotypes (Burdon 1977), will not be discussed further.
