It isn't possible to convert a bank account to a normal account (or vice versa). However, there are workaround steps you can follow instead, depending on your circumstances.
No entries or balances to date in the existing account?
The simplest solution in this instance is to delete the existing account. You can then recreate it with the same details (Code/Account Name/Class) as a bank account or account.
You can delete a bank account from the Chart of Accounts:
Go to Accountings > Chart of Accounts
Select the bank account and click Delete
Entries or balances to date in the existing account?
In this instance, it isn't possible to delete the existing account.
Instead, you can follow the alternative steps below.
If you need to keep the same code for your new account, change the code on the existing account to a new redundant code (one you won't want to use again).
Add the new account you want (either a bank account type or normal account type).
Reduce the old account balance to NIL by adding a single bank statement batch entry line (either a payment or receipt amount) to the normal account to clear it.
If there was a balance in the account to start, everything will then be switched and you'll have the account in the format you require for future entries.
In the next period (after you close and roll forward this period, via period-end routine) you can deactivate the old account.
📎NOTE: It isn't possible to deactivate it in the current period if you performed the entry to remove any remaining balance. See below:
