How You Can Reset The Sequence Number For The REQUEST_ID

Ensure that you have a current system backup prior to performing this
process.
1-Log in to SQLPLUS as apps/'apps password'.
2-SQL> drop sequence fnd_concurrent_requests_s;
3-SQL> create sequence fnd_concurrent_requests_s
start with xxxx;

4-Check the sequences again.

SQL> select max(request_id) from fnd_concurrent_requests;
from system.dual;

NOTE: The value from step 4 should be bigger than value from step 3.