My data is like this. I have to remap the unscheduled visits to the closest scheduled visit that is missing. Unscheduled visit of 2 on aDDY=1 can not be re-mapped, since we already have the screening visit.  The unscheduled visit on ADDY=108 for 0 can be re-mapped to Day 85 . The unscheduled visit for 1 on day 57 can be re-mapped to Day 43.   Can someone guide how to proceed... SUB   VISITNUM  VISIT         AVISIT        ADDY  ---------------------------------------------------------------------------------------   2         2  Screening     Screening      -14    2        11  Day 43        Day 43          43    2        18  Day 85        Day 85     91    2        99  Unscheduled   Unscheduled      1    7         2  Screening     Screening      -12    7        11  Day 43        Day 43          43    7        18  Day 85        Day 85          87    7        99  Unscheduled   Unscheduled      9    0         2  Screening     Screening      -12    0        11  Day 43        Day 43          39    0        99  Unscheduled   Unscheduled    108    3         2  Screening     Screening       -5    3        11  Day 43        Day 43          45    3        18  Day 85 (EOT)  Day 85 (EOT)    85    3        99  Unscheduled   Unscheduled     99    1         2  Screening     Screening      -51    1        18  Day 85 (EOT)  Day 85 (EOT)    84    1        99  Unscheduled   Unscheduled     57 ... View more