Moving partition to a new filegroup - sql-server

Question

I have a huge table which is partitioned by date.
We have 8 partitions all on different file groups, with one of these file groups being PRIMARY.
I would like to replace the PRIMARY file group with a new file group called 'FG_odsvr_misc', and remove PRIMARY from the partition schema.
How would i achieve this without creating a new table with a new partition function?
The boundaries look like below -
The partition function is as below -
CREATE PARTITION FUNCTION [fn_odstable1](numeric(9,0))
AS RANGE LEFT FOR VALUES (20151231, 20161231, 20171231, 20181231, 20191231, 20201231, 20211231)
The partition scheme is as below -
CREATE PARTITION SCHEME [sch_odstable1] AS PARTITION [fn_odstable1]
TO ([FG_odsvr_pre_2016], [FG_odsvr_2016], [FG_odsvr_2017], [FG_odsvr_2018], [FG_odsvr_2019], [FG_odsvr_2020], [FG_odsvr_2021], [PRIMARY])

Answer 1

Ok. The partition you have on the PRIMARY filegroup is the so-called "Permanent Partition"
From Dan Guzman's Table Partitioning Best Practices:
You might not be aware that each partition scheme has a permanent
partition that can never be removed. This is the first partition of a
RANGE RIGHT function and the last partition of a RANGE LEFT one. Be
mindful of this permanent partition when creating a new partition
scheme when multiple filegroups are involved because the filegroup on
which this permanent partition is created is determined when the
partition scheme is created and cannot be removed from the scheme.
. . .
Consider mapping partitions containing data outside the expected range
to a dummy filegroup with no underlying files. This will guarantee
data integrity much like a check constraint because data outside the
allowable range cannot be inserted. If you must accommodate errant
data rather than rejecting it outright, instead map these partitions
to a generalized filegroup like DEFAULT or one designated specifically
for that purpose.
http://www.dbdelta.com/table-partitioning-best-practices/
Since this is a RANGE LEFT partition scheme you can move all the data off of PRIMARY onto a new filegroup by splitting the rightmost partition at a boundary point greater than the greatest value present in your table.
ALTER PARTITION SCHEME sch_odstable1 NEXT USED [FG_odsvr_2022];
ALTER PARTITION FUNCTION fn_odstable1() SPLIT RANGE (20221231);
The rightmost partition will still be on PRIMARY though. You'll just need to create your future partitions before you need them to keep that partition empty. If you want to you can create a new Partition Scheme
alter database current add filegroup no_files_cant_be_used
CREATE PARTITION SCHEME [sch_odstable2] AS PARTITION [fn_odstable1]
TO ([FG_odsvr_pre_2016], [FG_odsvr_2016], [FG_odsvr_2017], [FG_odsvr_2018], [FG_odsvr_2019], [FG_odsvr_2020], [FG_odsvr_2021], [FG_odsvr_2022], no_files_cant_be_used)
And then create a matching table on the new scheme, ALTER TABLE SWITCH to move all the partitions to the new table, and then rename the tables.