During the Trans-Lunar Coast phase of an Apollo lunar landing mission, the Direct Abort is identified as the primary emergency return mode unless the spacecraft has entered the proximity of the lunar sphere of influence (SOI), after which point the "delay to post-pericynthion abort" becomes primary. The Direct Abort can be accomplished with large burn to a time-critical return trajectory, or with a smaller burn to a fuel-critical return trajectory.
See text at <a class="external autonumber" href="https://en.wikisource.org/wiki/APOLLO_LUNAR_LANDING_MISSION_SYMPOSIUM">[1]</a>
Ronald L. Berry
1966-06
APOLLO LUNAR LANDING MISSION SYMPOSIUM - JUNE 25-27, 1966 MSC - VOLUME II - APOLLO EARTH RETURN ABORT CAPABILITIES. <a rel="nofollow" class="external text" href="https://books.google.com/books?id=Xg0DAAAAIAAJ&amp;ppis=_e&amp;lpg=PP375&amp;ots=x1UycfXRXV&amp;dq=NASA-S-66-5153&amp;pg=PP160#v=onepage">Page 160</a>