Just another option to consider, think of it as food for thought:

with TestData as (

select

PassM,

cast(EnterDt as datetime) EnterDt,

ConsecutiveD

from

(values

('Boo K K','5/1/2012 11:55:00 PM', 1),

('Boo K K','5/2/2012 11:30:00 PM', 2),

('Boo K K','5/4/2012 10:30:00 AM', 1),

('LIAW S','4/30/2012 11:48:52 PM', 1),

('LIAW S','5/1/2012 00:11:07 AM', 2),

('LIAW S','5/1/2012 11:59:07 AM', 2),

('LIAW S','5/1/2012 4:42:02 AM', 2),

('LIAW S','5/2/2012 1:10:09 AM', 3),

('LIAW S','5/2/2012 1:43:06 AM', 3),

('LIAW S','5/4/2012 2:17:47 AM', 1)

)dt(PassM, EnterDt, ConsecutiveD)

)

, UniqueDts as (

select distinct

PassM,

dateadd(dd,datediff(dd,0,EnterDt),0) UniqEnterDt

from

TestData

)

, GrpDates as (

select

PassM,

UniqEnterDt,

GrpDate = dateadd(dd,row_number() over (partition by PassM order by UniqEnterDt) *-1,UniqEnterDt),

rn = row_number() over (partition by PassM order by UniqEnterDt)

from

UniqueDts

)

,ConsecutiveDts as (

select

PassM,

UniqEnterDt,

rn = row_number() over (partition by PassM, GrpDate order by UniqEnterDt)

from

GrpDates

)

select

td.PassM,

td.EnterDt,

cd.rn as CompConsecutiveD,

td.ConsecutiveD

from

TestData td

inner join ConsecutiveDts cd

on (td.PassM = cd.PassM and

dateadd(dd,datediff(dd,0,td.EnterDt),0) = cd.UniqEnterDt);