SQL Server query assistance needed

I'm storing a bunch of data in a view (converted MS Access queries to views). Now what I'm trying to do is write a stored procedure to pull data based on when the data was added. Here is the query that I'm running

Select 
    Name, PlanID, ApptDate, 1stAppt, rn, 
from 
    (Select 
         *,   
         row_number() over (partition by PlanID Order BY AddedonDate desc) as rn 
     From vClientInfo)

So this pulls all my data okay. The issue that I have to address is, the client actually comes in for the 1st appt and 2nd appt - Basically I need to pull the data for LATEST date, as well as EARLIEST, and include a '2ndAppt' in my query. So 1stAppt and 2ndAppt hold a string value that I will later use...The 2 values might differ from 1stAppt to 2ndAppt - and only AddedOn date will tell me if there was a different (earliest for 1stAppt, and latest for 2ndAppt).

Select 
    Name, PlanID, ApptDate, 1stAppt, 2ndAppt rn, 
From 
    (Select 
         *, 
         row_number() over (partition by PlanID Order BY AddedonDate desc) as rn 
     From  vClientInfp)

So I did this and I changed this...

(Select *,  row_number() over (partition by PlanID Order BY AddedonDate *ASC*)

However I'm not sure if this is pulling correct data as I'm working with a lot of data and hard to verify. So basically I need to do a union so that both my queries pull in the correct data. Originally I was getting 1920 records, so with a union i should be getting just as many too i assume, however, the number is double so 3840, why?

Select 
    Name, PlanID, ApptDate, 1stAppt, 2ndappt, rn, 
From 
    (Select 
         *,   
         row_number() over (partition by PlanID Order BY AddedonDate desc) as rn 
     From  vClientInfo

     Union All

     Select 
         Name, PlanID, ApptDate, 1stAppt, 2ndAppt, rn, 
     From 
         (Select 
              *,  
              row_number() over (partition by PlanID Order BY AddedonDate asc) as rn 
          From vClientInfo

You are using window function, but you are not filtering by it, so whats the point? If you want the earliest and the latest, choose rn = 1 :

Select Name, PlanID, ApptDate, 1stAppt,2ndappt, rn,
from (Select *,
            row_number() over (partition by PlanID Order BY AddedonDate desc) as rn
     from  vClientInfo
     Union All
     Select *, 
           row_number() over (partition by PlanID Order BY AddedonDate asc) as rn 
     from  vClientInfo)
WHERE rn = 1

If you want 1st appt from the earliest and 2ndappt from the latest :

Select Name, PlanID, ApptDate,
       MAX(CASE WHEN rnk = 1 then 1stAppt end) as 1stAppt,
       MAX(CASE WHEN rn = 1 THEN 2ndappt end) as 2ndAppt
from (Select *,
            row_number() over (partition by PlanID Order BY AddedonDate desc) as rn,
     0 as rnk
     from  vClientInfo
     Union All
     Select *,
           0 as rn,
           row_number() over (partition by PlanID Order BY AddedonDate asc) as rnk 
     from  vClientInfo)
GROUP BY Name,PlanID,ApptDate