The documentation doesn't currently say how to reset gtid_current_pos:
gtid_current_pos is made up by combining GTIDs from two different variables: gtid_binlog_pos and gtid_slave_pos. So to reset gtid_current_pos, you need to reset both of those.
1.) gtid_binlog_pos can be reset with "RESET MASTER":
2.) gtid_slave_pos can be reset by executing: