This depends on your reason:
Several third-party tools claim to change your Steam ID. However, be cautious when using these tools, as they might: steam id changer cs 16 full
Changing IDs to bypass bans is considered "ban evading" and can lead to a permanent blacklist from entire server networks. This depends on your reason: Several third-party tools
Join the server’s Discord or forum. Many admins unban players who admit their mistake (e.g., accidental team kill, misunderstood rule). be cautious when using these tools