"Granting that" is a common phrase used to introduce a conditional statement. However, if you want to avoid repetition in your writing, there are several synonyms you can use instead. Some examples include "assuming that," "acknowledging that," "accepting that," "conceding that," and "granted that." Each of these phrases can be used in place of "granting that" to add variety and keep your writing interesting. Depending on the context of your writing, some synonyms may be more appropriate than others, so be sure to consider the tone and purpose of your work before choosing a replacement.