I have an upcoming flight HKG - IST - LHR. Now, I have two mileage accounts, one for personal use and it is Star Gold. The other one is for work and it is basic status (after 3 years of travel bans). Can I check in using my personal account and then try to change the account after lounge access at IST? (I cannot credit a flight for work to my personal account.) If not, is there a pay per use shower facility at IST?