In the Name of Allah, Most Gracious, Most Merciful.
All praise and thanks are due to Allah, and peace and blessings be upon His Messenger.
In this fatwa:
Answering your question, the General Iftaa’ Department in Jordan, states the following:
Therefore, it is permissible to make wudu (ablution) without answering the call of nature. However, prayer is invalidated if there is impurity on the anus or the front opening, so this impurity must be removed for the prayer to become valid.
Almighty Allah knows best.