How many times can a user change his, or her, profile name? I have just done it once, but want to know how many times I can do it again
Is there is a specific limit on changing a profile name?
No, there is no limit. You can change your profile name as many times as you want. But keep in mind that once you change your profile name, you have to wait 30 days to change it again.
The change name history you can see below your "helpful flag" count as recent name. The recent names is available for next 90 days.
Advice: Stack Overflow is a Q/A site not a Social Networking site, so you better not change your profile name frequently.