I am not sure that Partition Magic would be able to resize the Linux Partitions if he has some.
Or, is it possible to resize any partition of a running system?
Do you really mean the word "any" here?
If you are talking about NTFS and FAT32, it can be done with the Partition Magic 8 (Reliability quite less ). I don't know about the lower versions of Partition Magic.
But not all versions are reliable, and they cause damage to the partitions if anything goes wrong, which is quite unpredictable.
So I recommend you first back-up all of your Data and then proceed.